<?xml version="1.0" encoding="US-ASCII"?>
<!-- RR Donnelley Xcelerate Taxonomy Calculation Linkbase, based on XBRL 2.1  http://www.rrdonnelley.com/ -->
<!-- Version: 6.22.4 -->
<!-- Round: 0355b536-1980-413b-b23b-2da763726605 -->
<!-- Creation date: 2015-11-05T02:33:18Z -->
<!-- Copyright (c) 2005-2013 R.R. Donnelley & Sons Company All Rights Reserved. -->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DocumentandEntityInformation" roleURI="http://www.swgas.com/taxonomy/role/DocumentandEntityInformation"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_StatementOfFinancialPositionClassified" roleURI="http://www.swgas.com/taxonomy/role/StatementOfFinancialPositionClassified"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_StatementOfFinancialPositionClassifiedParen" roleURI="http://www.swgas.com/taxonomy/role/StatementOfFinancialPositionClassifiedParenthetical"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_StatementOfIncomeAlternative" roleURI="http://www.swgas.com/taxonomy/role/StatementOfIncomeAlternative"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_StatementOfPartnersCapital" roleURI="http://www.swgas.com/taxonomy/role/StatementOfPartnersCapital"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_StatementOfCashFlowsIndirect" roleURI="http://www.swgas.com/taxonomy/role/StatementOfCashFlowsIndirect"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureNatureOfOperationsAndBasisOfPresentationAdditionalInformation" roleURI="http://www.swgas.com/taxonomy/role/DisclosureNatureOfOperationsAndBasisOfPresentationAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureNatureOfOperationsAndBasisOfPresentationScheduleOfGoodwill" roleURI="http://www.swgas.com/taxonomy/role/DisclosureNatureOfOperationsAndBasisOfPresentationScheduleOfGoodwill"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureNatureOfOperationsAndBasisOfPresentationIntercompanyTransactions" roleURI="http://www.swgas.com/taxonomy/role/DisclosureNatureOfOperationsAndBasisOfPresentationIntercompanyTransactions"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureNatureOfOperationsAndBasisOfPresentationScheduleOfOtherPropertyAndInvestments" roleURI="http://www.swgas.com/taxonomy/role/DisclosureNatureOfOperationsAndBasisOfPresentationScheduleOfOtherPropertyAndInvestments"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureNatureOfOperationsAndBasisOfPresentationOtherIncomeDeductions" roleURI="http://www.swgas.com/taxonomy/role/DisclosureNatureOfOperationsAndBasisOfPresentationOtherIncomeDeductions"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureComponentsOfNetPeriodicBenefitCostScheduleOfComponentsOfNetPeriodicBenefitCosts" roleURI="http://www.swgas.com/taxonomy/role/DisclosureComponentsOfNetPeriodicBenefitCostScheduleOfComponentsOfNetPeriodicBenefitCosts"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureSegmentInformationScheduleOfSegmentReportingInformation" roleURI="http://www.swgas.com/taxonomy/role/DisclosureSegmentInformationScheduleOfSegmentReportingInformation"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureDerivativesAndFairValueMeasurementsAdditionalInformation" roleURI="http://www.swgas.com/taxonomy/role/DisclosureDerivativesAndFairValueMeasurementsAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureDerivativesAndFairValueMeasurementsNotionalAmountsUnderSwapsContracts" roleURI="http://www.swgas.com/taxonomy/role/DisclosureDerivativesAndFairValueMeasurementsNotionalAmountsUnderSwapsContracts"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureDerivativesAndFairValueMeasurementsAmountOfGainOrLossesRecognizedInIncomeOnDerivatives" roleURI="http://www.swgas.com/taxonomy/role/DisclosureDerivativesAndFairValueMeasurementsAmountOfGainOrLossesRecognizedInIncomeOnDerivatives"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureDerivativesAndFairValueMeasurementsFairValuesOfSwapsInCondensedConsolidatedBalanceSheets" roleURI="http://www.swgas.com/taxonomy/role/DisclosureDerivativesAndFairValueMeasurementsFairValuesOfSwapsInCondensedConsolidatedBalanceSheets"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureDerivativesAndFairValueMeasurementsPaidToAndReceivedFromCounterpartiesForSettlementsOfMaturedSwaps" roleURI="http://www.swgas.com/taxonomy/role/DisclosureDerivativesAndFairValueMeasurementsPaidToAndReceivedFromCounterpartiesForSettlementsOfMaturedSwaps"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureDerivativesAndFairValueMeasurementsRegulatoryAssetsLiabilitiesOffsettingDerivativesAtFairValueInCondensedConsolidatedBalanceSheets" roleURI="http://www.swgas.com/taxonomy/role/DisclosureDerivativesAndFairValueMeasurementsRegulatoryAssetsLiabilitiesOffsettingDerivativesAtFairValueInCondensedConsolidatedBalanceSheets"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureDerivativesAndFairValueMeasurementsSignificantOtherObservableInputs" roleURI="http://www.swgas.com/taxonomy/role/DisclosureDerivativesAndFairValueMeasurementsSignificantOtherObservableInputs"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureCommonStockAdditionalInformation" roleURI="http://www.swgas.com/taxonomy/role/DisclosureCommonStockAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureLongTermDebtScheduleOfCarryingAmountsAndEstimatedFairValuesOfLongTermDebt" roleURI="http://www.swgas.com/taxonomy/role/DisclosureLongTermDebtScheduleOfCarryingAmountsAndEstimatedFairValuesOfLongTermDebt"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureLongTermDebtScheduleOfCarryingAmountsAndEstimatedFairValuesOfLongTermDebtAlt1" roleURI="http://www.swgas.com/taxonomy/role/DisclosureLongTermDebtScheduleOfCarryingAmountsAndEstimatedFairValuesOfLongTermDebtAlternate1"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureLongTermDebtScheduleOfCarryingAmountsAndEstimatedFairValuesOfLongTermDebtParenthetical" roleURI="http://www.swgas.com/taxonomy/role/DisclosureLongTermDebtScheduleOfCarryingAmountsAndEstimatedFairValuesOfLongTermDebtParenthetical"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureLongTermDebtAdditionalInformation" roleURI="http://www.swgas.com/taxonomy/role/DisclosureLongTermDebtAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeDetailedActivitiesOfEquityAndRedeemableNoncontrollingInterest" roleURI="http://www.swgas.com/taxonomy/role/DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeDetailedActivitiesOfEquityAndRedeemableNoncontrollingInterest"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeDetailedActivitiesOfEquityAndRedeemableNoncontrollingInterestParenthetical" roleURI="http://www.swgas.com/taxonomy/role/DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeDetailedActivitiesOfEquityAndRedeemableNoncontrollingInterestParenthetical"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeRelatedTaxEffectsAllocatedToEachComponentOfOtherComprehensiveIncomeLoss" roleURI="http://www.swgas.com/taxonomy/role/DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeRelatedTaxEffectsAllocatedToEachComponentOfOtherComprehensiveIncomeLoss"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeRelatedTaxEffectsAllocatedToEachComponentOfOtherComprehensiveIncomeLossParenthetical" roleURI="http://www.swgas.com/taxonomy/role/DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeRelatedTaxEffectsAllocatedToEachComponentOfOtherComprehensiveIncomeLossParenthetical"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeAdditionalInformation" roleURI="http://www.swgas.com/taxonomy/role/DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeRollforwardOfAccumulatedOtherComprehensiveIncome" roleURI="http://www.swgas.com/taxonomy/role/DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeRollforwardOfAccumulatedOtherComprehensiveIncome"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeAmountRecognizedBeforeIncomeTaxAssociatedWithDefinedBenefitPlansInAccumulatedOtherComprehensiveIncome" roleURI="http://www.swgas.com/taxonomy/role/DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeAmountRecognizedBeforeIncomeTaxAssociatedWithDefinedBenefitPlansInAccumulatedOtherComprehensiveIncome"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureAcquisitionOfConstructionServicesBusinessesAdditionalInformation" roleURI="http://www.swgas.com/taxonomy/role/DisclosureAcquisitionOfConstructionServicesBusinessesAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureConstructionServicesRedeemableNoncontrollingInterestsAdditionalInformation" roleURI="http://www.swgas.com/taxonomy/role/DisclosureConstructionServicesRedeemableNoncontrollingInterestsAdditionalInformation"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#DisclosureConstructionServicesRedeemableNoncontrollingInterestsSummaryOfRedeemableNoncontrollingInterest" roleURI="http://www.swgas.com/taxonomy/role/DisclosureConstructionServicesRedeemableNoncontrollingInterestsSummaryOfRedeemableNoncontrollingInterest"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsOrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsOrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsOrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlockPolicies" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsOrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlockPolicies"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsOrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlockTables" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsOrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsNetPeriodicBenefitCostDisclosureTextBlock" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsNetPeriodicBenefitCostDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsNetPeriodicBenefitCostDisclosureTextBlockTables" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsNetPeriodicBenefitCostDisclosureTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsSegmentReportingDisclosureTextBlock" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsSegmentReportingDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsSegmentReportingDisclosureTextBlockTables" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsSegmentReportingDisclosureTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsDerivativesAndFairValueTextBlock" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsDerivativesAndFairValueTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsDerivativesAndFairValueTextBlockTables" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsDerivativesAndFairValueTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsCommonStockDisclosureTextBlock" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsCommonStockDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsLongTermDebtTextBlock" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsLongTermDebtTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsLongTermDebtTextBlockTables" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsLongTermDebtTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsStockholdersEquityNoteDisclosureTextBlock" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsStockholdersEquityNoteDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsStockholdersEquityNoteDisclosureTextBlockTables" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsStockholdersEquityNoteDisclosureTextBlockTables"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsBusinessCombinationDisclosureTextBlock" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsBusinessCombinationDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsMinorityInterestDisclosureTextBlock" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsMinorityInterestDisclosureTextBlock"/>
  <roleRef xlink:type="simple" xlink:href="swx-20150930.xsd#Role_NotesToFinancialStatementsMinorityInterestDisclosureTextBlockTables" roleURI="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsMinorityInterestDisclosureTextBlockTables"/>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DocumentandEntityInformation">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/StatementOfFinancialPositionClassified">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="us-gaap_AccountsPayableCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="us-gaap_AccountsReceivableNetCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccrualForTaxesOtherThanIncomeTaxesCurrent" xlink:label="us-gaap_AccrualForTaxesOtherThanIncomeTaxesCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_Assets" xlink:label="us-gaap_Assets"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="us-gaap_AssetsCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AssetsNoncurrent" xlink:label="us-gaap_AssetsNoncurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CapitalizationLongtermDebtAndEquity" xlink:label="us-gaap_CapitalizationLongtermDebtAndEquity"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CommonStockValue" xlink:label="us-gaap_CommonStockValue"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CustomerDepositsCurrent" xlink:label="us-gaap_CustomerDepositsCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredCreditsAndOtherLiabilitiesNoncurrent" xlink:label="us-gaap_DeferredCreditsAndOtherLiabilitiesNoncurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredGasCost" xlink:label="us-gaap_DeferredGasCost"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredGasPurchasesCurrent" xlink:label="us-gaap_DeferredGasPurchasesCurrent"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_DeferredIncomeTaxesAndUnamortizedInvestmentTaxCredits" xlink:label="swx_DeferredIncomeTaxesAndUnamortizedInvestmentTaxCredits"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredTaxAssetsNetCurrent" xlink:label="us-gaap_DeferredTaxAssetsNetCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredTaxAssetsNetNoncurrent" xlink:label="us-gaap_DeferredTaxAssetsNetNoncurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredTaxLiabilitiesGrossCurrent" xlink:label="us-gaap_DeferredTaxLiabilitiesGrossCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_Goodwill" xlink:label="us-gaap_Goodwill"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeTaxesReceivable" xlink:label="us-gaap_IncomeTaxesReceivable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestPayableCurrent" xlink:label="us-gaap_InterestPayableCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="us-gaap_LiabilitiesCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="us-gaap_LongTermDebtCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="us-gaap_LongTermDebtNoncurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MinorityInterest" xlink:label="us-gaap_MinorityInterest"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherAccruedLiabilitiesNoncurrent" xlink:label="us-gaap_OtherAccruedLiabilitiesNoncurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="us-gaap_OtherAssetsNoncurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherLiabilitiesCurrent" xlink:label="us-gaap_OtherLiabilitiesCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="us-gaap_OtherLiabilitiesNoncurrent"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherPropertyAndInvestments" xlink:label="swx_OtherPropertyAndInvestments"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherReceivables" xlink:label="us-gaap_OtherReceivables"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation" xlink:label="us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAmountOfAcquisitionAdjustments1" xlink:label="us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAmountOfAcquisitionAdjustments1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress" xlink:label="us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet" xlink:label="us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService" xlink:label="us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount" xlink:label="us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalents" xlink:label="us-gaap_RestrictedCashAndCashEquivalents"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShortTermBorrowings" xlink:label="us-gaap_ShortTermBorrowings"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="us-gaap_StockholdersEquity"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_TaxesPayableCurrent" xlink:label="us-gaap_TaxesPayableCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet" order="1.0500" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="swx_OtherPropertyAndInvestments" order="1.0600" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_RestrictedCashAndCashEquivalents" order="1.0700" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_AssetsCurrent" order="1.1500" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_AssetsNoncurrent" order="1.1900" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue" order="1.0800" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_AccountsReceivableNetCurrent" order="1.0900" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_OtherReceivables" order="1.1000" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_IncomeTaxesReceivable" order="1.1100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_DeferredTaxAssetsNetCurrent" order="1.1200" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_DeferredGasCost" order="1.1300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" order="1.1400" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="us-gaap_Goodwill" order="1.1600" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="us-gaap_DeferredTaxAssetsNetNoncurrent" order="1.1700" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="us-gaap_OtherAssetsNoncurrent" order="1.1800" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CapitalizationLongtermDebtAndEquity" xlink:to="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" order="1.2600" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CapitalizationLongtermDebtAndEquity" xlink:to="us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount" order="1.2700" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CapitalizationLongtermDebtAndEquity" xlink:to="us-gaap_LongTermDebtNoncurrent" order="1.2800" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_CapitalizationLongtermDebtAndEquity" order="1.2900" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_LiabilitiesCurrent" order="1.4000" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_OtherLiabilitiesNoncurrent" order="1.4400" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_LongTermDebtCurrent" order="1.3000" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_ShortTermBorrowings" order="1.3100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_AccountsPayableCurrent" order="1.3200" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_CustomerDepositsCurrent" order="1.3300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_TaxesPayableCurrent" order="1.3400" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_AccrualForTaxesOtherThanIncomeTaxesCurrent" order="1.3500" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_InterestPayableCurrent" order="1.3600" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_DeferredTaxLiabilitiesGrossCurrent" order="1.3700" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_DeferredGasPurchasesCurrent" order="1.3800" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_OtherLiabilitiesCurrent" order="1.3900" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherLiabilitiesNoncurrent" xlink:to="swx_DeferredIncomeTaxesAndUnamortizedInvestmentTaxCredits" order="1.4100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherLiabilitiesNoncurrent" xlink:to="us-gaap_OtherAccruedLiabilitiesNoncurrent" order="1.4200" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherLiabilitiesNoncurrent" xlink:to="us-gaap_DeferredCreditsAndOtherLiabilitiesNoncurrent" order="1.4300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet" xlink:to="us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService" order="1.0100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet" xlink:to="us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation" order="1.0200" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet" xlink:to="us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAmountOfAcquisitionAdjustments1" order="1.0300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet" xlink:to="us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress" order="1.0400" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_CommonStockValue" order="1.2000" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_AdditionalPaidInCapitalCommonStock" order="1.2100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" order="1.2200" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit" order="1.2300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="us-gaap_StockholdersEquity" order="1.2400" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="us-gaap_MinorityInterest" order="1.2500" weight="1.00" priority="2" use="optional"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/StatementOfFinancialPositionClassifiedParenthetical">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/StatementOfIncomeAlternative">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConstructionAndDevelopmentCosts" xlink:label="us-gaap_ConstructionAndDevelopmentCosts"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConstructionRevenue" xlink:label="us-gaap_ConstructionRevenue"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CostsAndExpenses" xlink:label="us-gaap_CostsAndExpenses"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DepreciationAndAmortization" xlink:label="us-gaap_DepreciationAndAmortization"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="us-gaap_IncomeTaxExpenseBenefit"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestExpense" xlink:label="us-gaap_InterestExpense"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="us-gaap_NonoperatingIncomeExpense"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="us-gaap_OperatingIncomeLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="us-gaap_OtherNonoperatingIncomeExpense"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProfitLoss" xlink:label="us-gaap_ProfitLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RegulatedAndUnregulatedOperatingRevenue" xlink:label="us-gaap_RegulatedAndUnregulatedOperatingRevenue"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RegulatedOperatingRevenueGas" xlink:label="us-gaap_RegulatedOperatingRevenueGas"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_TaxesExcludingIncomeAndExciseTaxes" xlink:label="us-gaap_TaxesExcludingIncomeAndExciseTaxes"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_UtilitiesOperatingExpenseGasAndPetroleumPurchased" xlink:label="us-gaap_UtilitiesOperatingExpenseGasAndPetroleumPurchased"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_UtilitiesOperatingExpenseMaintenanceAndOperations" xlink:label="us-gaap_UtilitiesOperatingExpenseMaintenanceAndOperations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CostsAndExpenses" xlink:to="us-gaap_UtilitiesOperatingExpenseGasAndPetroleumPurchased" order="1.0400" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CostsAndExpenses" xlink:to="us-gaap_UtilitiesOperatingExpenseMaintenanceAndOperations" order="1.0500" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CostsAndExpenses" xlink:to="us-gaap_DepreciationAndAmortization" order="1.0600" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CostsAndExpenses" xlink:to="us-gaap_TaxesExcludingIncomeAndExciseTaxes" order="1.0700" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CostsAndExpenses" xlink:to="us-gaap_ConstructionAndDevelopmentCosts" order="1.0800" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="us-gaap_OperatingIncomeLoss" order="1.1000" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="us-gaap_NonoperatingIncomeExpense" order="1.1300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss" xlink:to="us-gaap_ProfitLoss" order="1.1600" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss" xlink:to="us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" order="1.1700" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="us-gaap_InterestExpense" order="1.1100" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="us-gaap_OtherNonoperatingIncomeExpense" order="1.1200" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingIncomeLoss" xlink:to="us-gaap_RegulatedAndUnregulatedOperatingRevenue" order="1.0300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingIncomeLoss" xlink:to="us-gaap_CostsAndExpenses" order="1.0900" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ProfitLoss" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" order="1.1400" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ProfitLoss" xlink:to="us-gaap_IncomeTaxExpenseBenefit" order="1.1500" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_RegulatedAndUnregulatedOperatingRevenue" xlink:to="us-gaap_RegulatedOperatingRevenueGas" order="1.0100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_RegulatedAndUnregulatedOperatingRevenue" xlink:to="us-gaap_ConstructionRevenue" order="1.0200" weight="1.00" priority="2" use="optional"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/StatementOfPartnersCapital">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" xlink:label="us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:label="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeDefinedBenefitPlansRegulatoryAdjustmentNetOfTax" xlink:label="swx_OtherComprehensiveIncomeDefinedBenefitPlansRegulatoryAdjustmentNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProfitLoss" xlink:label="us-gaap_ProfitLoss"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" order="1.1200" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" order="1.1300" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:to="us-gaap_ProfitLoss" order="1.0100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:to="us-gaap_OtherComprehensiveIncomeLossNetOfTax" order="1.1100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" order="1.0700" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax" order="1.0900" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" order="1.1000" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax" order="1.0200" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax" order="1.0300" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax" order="1.0400" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax" order="1.0500" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:to="swx_OtherComprehensiveIncomeDefinedBenefitPlansRegulatoryAdjustmentNetOfTax" order="1.0600" weight="1.00" priority="2" use="optional"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/StatementOfCashFlowsIndirect">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_ChangeInCustomerAdvances" xlink:label="swx_ChangeInCustomerAdvances"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DepreciationAndAmortization" xlink:label="us-gaap_DepreciationAndAmortization"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations" xlink:label="us-gaap_EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:label="us-gaap_GainLossOnSaleOfPropertyPlantEquipment"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInAllowanceForEquityFundsUsedDuringConstruction" xlink:label="us-gaap_IncreaseDecreaseInAllowanceForEquityFundsUsedDuringConstruction"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredGasCost" xlink:label="us-gaap_IncreaseDecreaseInDeferredGasCost"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredIncomeTaxes" xlink:label="us-gaap_IncreaseDecreaseInDeferredIncomeTaxes"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssets"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingLiabilities" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInOtherReceivables" xlink:label="us-gaap_IncreaseDecreaseInOtherReceivables"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInPropertyAndOtherTaxesPayable" xlink:label="us-gaap_IncreaseDecreaseInPropertyAndOtherTaxesPayable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInRestrictedCash" xlink:label="us-gaap_IncreaseDecreaseInRestrictedCash"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_PaymentsForMiscellaneousInvestingActivities" xlink:label="swx_PaymentsForMiscellaneousInvestingActivities"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PaymentsOfDividendsCommonStock" xlink:label="us-gaap_PaymentsOfDividendsCommonStock"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt" xlink:label="us-gaap_ProceedsFromIssuanceOfLongTermDebt"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_ProceedsFromMiscellaneousInvestingActivities" xlink:label="swx_ProceedsFromMiscellaneousInvestingActivities"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromPaymentsForOtherFinancingActivities" xlink:label="us-gaap_ProceedsFromPaymentsForOtherFinancingActivities"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_ProceedsFromRepaymentsOfLinesOfCreditAndCommercialPaper" xlink:label="swx_ProceedsFromRepaymentsOfLinesOfCreditAndCommercialPaper"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromRepaymentsOfShortTermDebt" xlink:label="us-gaap_ProceedsFromRepaymentsOfShortTermDebt"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProfitLoss" xlink:label="us-gaap_ProfitLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepaymentsOfDebtAndCapitalLeaseObligations" xlink:label="us-gaap_RepaymentsOfDebtAndCapitalLeaseObligations"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepaymentsOfLongTermDebt" xlink:label="us-gaap_RepaymentsOfLongTermDebt"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="us-gaap_ShareBasedCompensation"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" order="1.1500" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" order="1.2200" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" order="1.3100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:to="us-gaap_EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations" order="1.3200" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:to="us-gaap_ProceedsFromIssuanceOfCommonStock" order="1.2300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:to="us-gaap_PaymentsOfDividendsCommonStock" order="1.2400" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:to="us-gaap_ProceedsFromIssuanceOfLongTermDebt" order="1.2500" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:to="us-gaap_RepaymentsOfLongTermDebt" order="1.2600" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:to="swx_ProceedsFromRepaymentsOfLinesOfCreditAndCommercialPaper" order="1.2700" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:to="us-gaap_ProceedsFromRepaymentsOfShortTermDebt" order="1.2800" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:to="us-gaap_RepaymentsOfDebtAndCapitalLeaseObligations" order="1.2900" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:to="us-gaap_ProceedsFromPaymentsForOtherFinancingActivities" order="1.3000" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" order="1.1600" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:to="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" order="1.1700" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInRestrictedCash" order="1.1800" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:to="swx_ChangeInCustomerAdvances" order="1.1900" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:to="swx_ProceedsFromMiscellaneousInvestingActivities" order="1.2000" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:to="swx_PaymentsForMiscellaneousInvestingActivities" order="1.2100" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_ProfitLoss" order="1.0100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_DepreciationAndAmortization" order="1.0200" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInDeferredIncomeTaxes" order="1.0300" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInAccountsReceivable" order="1.0400" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInOtherReceivables" order="1.0500" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInDeferredGasCost" order="1.0600" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInAccountsPayable" order="1.0700" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInPropertyAndOtherTaxesPayable" order="1.0800" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" order="1.0900" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_GainLossOnSaleOfPropertyPlantEquipment" order="1.1000" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_ShareBasedCompensation" order="1.1100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInAllowanceForEquityFundsUsedDuringConstruction" order="1.1200" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInOtherOperatingAssets" order="1.1300" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities" order="1.1400" weight="1.00" priority="2" use="optional"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureNatureOfOperationsAndBasisOfPresentationAdditionalInformation">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureNatureOfOperationsAndBasisOfPresentationScheduleOfGoodwill">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureNatureOfOperationsAndBasisOfPresentationIntercompanyTransactions">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureNatureOfOperationsAndBasisOfPresentationScheduleOfOtherPropertyAndInvestments">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CashSurrenderValueOfLifeInsurance" xlink:label="us-gaap_CashSurrenderValueOfLifeInsurance"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherPropertyAndInvestments" xlink:label="swx_OtherPropertyAndInvestments"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="us-gaap_PropertyPlantAndEquipmentGross"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentOtherNet" xlink:label="us-gaap_PropertyPlantAndEquipmentOtherNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherPropertyAndInvestments" xlink:to="us-gaap_PropertyPlantAndEquipmentGross" order="1.0100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherPropertyAndInvestments" xlink:to="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" order="1.0200" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherPropertyAndInvestments" xlink:to="us-gaap_CashSurrenderValueOfLifeInsurance" order="1.0300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherPropertyAndInvestments" xlink:to="us-gaap_PropertyPlantAndEquipmentOtherNet" order="1.0400" weight="1.00" priority="2" use="optional"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureNatureOfOperationsAndBasisOfPresentationOtherIncomeDeductions">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ForeignCurrencyTransactionGainLossRealized" xlink:label="us-gaap_ForeignCurrencyTransactionGainLossRealized"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestIncomeOther" xlink:label="us-gaap_InterestIncomeOther"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LifeInsuranceCorporateOrBankOwnedChangeInValue" xlink:label="us-gaap_LifeInsuranceCorporateOrBankOwnedChangeInValue"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_MiscellaneousIncomeExpense" xlink:label="swx_MiscellaneousIncomeExpense"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="us-gaap_OtherNonoperatingIncomeExpense"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherNonoperatingIncomeExpense" xlink:to="us-gaap_LifeInsuranceCorporateOrBankOwnedChangeInValue" order="1.0100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherNonoperatingIncomeExpense" xlink:to="us-gaap_InterestIncomeOther" order="1.0200" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherNonoperatingIncomeExpense" xlink:to="us-gaap_ForeignCurrencyTransactionGainLossRealized" order="1.0300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherNonoperatingIncomeExpense" xlink:to="swx_MiscellaneousIncomeExpense" order="1.0400" weight="1.00" priority="2" use="optional"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureComponentsOfNetPeriodicBenefitCostScheduleOfComponentsOfNetPeriodicBenefitCosts">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:label="us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:label="us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:label="us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost" xlink:label="us-gaap_DefinedBenefitPlanInterestCost"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:label="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost" xlink:label="us-gaap_DefinedBenefitPlanServiceCost"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="us-gaap_DefinedBenefitPlanServiceCost" order="1.0100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="us-gaap_DefinedBenefitPlanInterestCost" order="1.0200" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" order="1.0300" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" order="1.0400" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" order="1.0500" weight="-1.00" priority="2" use="optional"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureSegmentInformationScheduleOfSegmentReportingInformation">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureDerivativesAndFairValueMeasurementsAdditionalInformation">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureDerivativesAndFairValueMeasurementsNotionalAmountsUnderSwapsContracts">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureDerivativesAndFairValueMeasurementsAmountOfGainOrLossesRecognizedInIncomeOnDerivatives">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureDerivativesAndFairValueMeasurementsFairValuesOfSwapsInCondensedConsolidatedBalanceSheets">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue" xlink:label="us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue" xlink:label="us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherDerivativesNotDesignatedAsHedgingInstrumentsAtFairValueNet" xlink:label="us-gaap_OtherDerivativesNotDesignatedAsHedgingInstrumentsAtFairValueNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherDerivativesNotDesignatedAsHedgingInstrumentsAtFairValueNet" xlink:to="us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue" order="1.0100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherDerivativesNotDesignatedAsHedgingInstrumentsAtFairValueNet" xlink:to="us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue" order="1.0200" weight="-1.00" priority="2" use="optional"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureDerivativesAndFairValueMeasurementsPaidToAndReceivedFromCounterpartiesForSettlementsOfMaturedSwaps">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureDerivativesAndFairValueMeasurementsRegulatoryAssetsLiabilitiesOffsettingDerivativesAtFairValueInCondensedConsolidatedBalanceSheets">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureDerivativesAndFairValueMeasurementsSignificantOtherObservableInputs">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureCommonStockAdditionalInformation">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureLongTermDebtScheduleOfCarryingAmountsAndEstimatedFairValuesOfLongTermDebt">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCredit" xlink:label="us-gaap_LineOfCredit"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongTermDebt" xlink:label="us-gaap_LongTermDebt"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NotesPayable" xlink:label="us-gaap_NotesPayable"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherLongTermDebt" xlink:label="us-gaap_OtherLongTermDebt"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SecuredDebt" xlink:label="us-gaap_SecuredDebt"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_UnsecuredDebt" xlink:label="us-gaap_UnsecuredDebt"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebt" xlink:to="us-gaap_UnsecuredDebt" order="1.0300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebt" xlink:to="us-gaap_NotesPayable" order="1.0500" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebt" xlink:to="us-gaap_LineOfCredit" order="1.0600" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebt" xlink:to="us-gaap_SecuredDebt" order="1.0800" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebt" xlink:to="us-gaap_OtherLongTermDebt" order="1.0900" weight="1.00" priority="2" use="optional"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureLongTermDebtScheduleOfCarryingAmountsAndEstimatedFairValuesOfLongTermDebtAlternate1">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongTermDebt" xlink:label="us-gaap_LongTermDebt"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="us-gaap_LongTermDebtCurrent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="us-gaap_LongTermDebtNoncurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebt" xlink:to="us-gaap_LongTermDebtCurrent" order="1.1000" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebt" xlink:to="us-gaap_LongTermDebtNoncurrent" order="1.1100" weight="1.00" priority="2" use="optional"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureLongTermDebtScheduleOfCarryingAmountsAndEstimatedFairValuesOfLongTermDebtParenthetical">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureLongTermDebtAdditionalInformation">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeDetailedActivitiesOfEquityAndRedeemableNoncontrollingInterest">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeDetailedActivitiesOfEquityAndRedeemableNoncontrollingInterestParenthetical">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeRelatedTaxEffectsAllocatedToEachComponentOfOtherComprehensiveIncomeLoss">
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_DefinedBenefitPlanRegulatoryAdjustmentBeforeTax" xlink:label="swx_DefinedBenefitPlanRegulatoryAdjustmentBeforeTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_DefinedBenefitPlanRegulatoryAdjustmentTaxExpenseOrBenefit" xlink:label="swx_DefinedBenefitPlanRegulatoryAdjustmentTaxExpenseOrBenefit"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodTax" xlink:label="swx_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax" xlink:label="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationAdjustmentTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationAdjustmentTaxPortionAttributableToParent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossBeforeTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" order="1.0600" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossBeforeTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax" order="1.0800" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossBeforeTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax" order="1.1000" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax" order="1.0100" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax" order="1.0200" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax" order="1.0300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:to="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax" order="1.0400" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:to="swx_DefinedBenefitPlanRegulatoryAdjustmentBeforeTax" order="1.0500" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:to="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax" order="1.1100" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax" order="1.1200" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTax" order="1.1300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:to="swx_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodTax" order="1.1400" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:to="swx_DefinedBenefitPlanRegulatoryAdjustmentTaxExpenseOrBenefit" order="1.1500" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" order="1.1600" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesTax" order="1.1800" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossTax" xlink:to="us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationAdjustmentTaxPortionAttributableToParent" order="1.2000" weight="1.00" priority="2" use="optional"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeRelatedTaxEffectsAllocatedToEachComponentOfOtherComprehensiveIncomeLossParenthetical">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeAdditionalInformation">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeRollforwardOfAccumulatedOtherComprehensiveIncome">
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_DefinedBenefitPlanRegulatoryAdjustmentBeforeTax" xlink:label="swx_DefinedBenefitPlanRegulatoryAdjustmentBeforeTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_DefinedBenefitPlanRegulatoryAdjustmentNetOfTaxAmount" xlink:label="swx_DefinedBenefitPlanRegulatoryAdjustmentNetOfTaxAmount"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_DefinedBenefitPlanRegulatoryAdjustmentTaxExpenseOrBenefit" xlink:label="swx_DefinedBenefitPlanRegulatoryAdjustmentTaxExpenseOrBenefit"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansTaxPortionAttributableToParent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesBeforeTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesBeforeTaxPortionAttributableToParent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPortionAttributableToParent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesTaxPortionAttributableToParent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToNoncontrollingInterest" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationAdjustmentTaxPortionAttributableToNoncontrollingInterest" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationAdjustmentTaxPortionAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationAdjustmentTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationAdjustmentTaxPortionAttributableToParent"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossAmortizationOfNetActuarialLossForeignCurrencyTranslationAdjustmentBeforeTax" xlink:label="swx_OtherComprehensiveIncomeLossAmortizationOfNetActuarialLossForeignCurrencyTranslationAdjustmentBeforeTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossAmortizationOfNetActuarialLossForeignCurrencyTranslationAdjustmentNetOfTax" xlink:label="swx_OtherComprehensiveIncomeLossAmortizationOfNetActuarialLossForeignCurrencyTranslationAdjustmentNetOfTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossAmortizationOfNetActuarialLossForeignCurrencyTranslationAdjustmentTax" xlink:label="swx_OtherComprehensiveIncomeLossAmortizationOfNetActuarialLossForeignCurrencyTranslationAdjustmentTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossAmortizationOfPriorServiceCostForeignCurrencyTranslationAdjustmentBeforeTax" xlink:label="swx_OtherComprehensiveIncomeLossAmortizationOfPriorServiceCostForeignCurrencyTranslationAdjustmentBeforeTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossAmortizationOfPriorServiceCostForeignCurrencyTranslationAdjustmentNetOfTax" xlink:label="swx_OtherComprehensiveIncomeLossAmortizationOfPriorServiceCostForeignCurrencyTranslationAdjustmentNetOfTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossAmortizationOfPriorServiceCostForeignCurrencyTranslationAdjustmentTax" xlink:label="swx_OtherComprehensiveIncomeLossAmortizationOfPriorServiceCostForeignCurrencyTranslationAdjustmentTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossDerivativesAdjustmentBeforeReclassificationAdjustmentsNetOfTax" xlink:label="swx_OtherComprehensiveIncomeLossDerivativesAdjustmentBeforeReclassificationAdjustmentsNetOfTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossDerivativesAdjustmentBeforeReclassificationAdjustmentsTax" xlink:label="swx_OtherComprehensiveIncomeLossDerivativesAdjustmentBeforeReclassificationAdjustmentsTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentBeforeTax" xlink:label="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentBeforeTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentNetOfTax" xlink:label="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentNetOfTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentTax" xlink:label="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentBeforeTax" xlink:label="swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentBeforeTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentBeforeTaxPortionAttributableToNoncontrollingInterest" xlink:label="swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentBeforeTaxPortionAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentNetOfTax" xlink:label="swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentNetOfTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:label="swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentTaxPortionAttributableToNoncontrollingInterest" xlink:label="swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentTaxPortionAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapsBeforeReclassificationAdjustmentsAndTax" xlink:label="swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapsBeforeReclassificationAdjustmentsAndTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsAndTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsAndTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBeforeReclassificationAdjustmentsTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBeforeReclassificationAdjustmentsTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentBeforeTax" xlink:label="swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentBeforeTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentBeforeTaxPortionAttributableToNoncontrollingInterest" xlink:label="swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentBeforeTaxPortionAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:label="swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentTax" xlink:label="swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentTaxPortionAttributableToNoncontrollingInterest" xlink:label="swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentTaxPortionAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossRegulatoryAdjustmentForeignCurrencyTranslationBeforeTax" xlink:label="swx_OtherComprehensiveIncomeLossRegulatoryAdjustmentForeignCurrencyTranslationBeforeTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossRegulatoryAdjustmentForeignCurrencyTranslationNetOfTax" xlink:label="swx_OtherComprehensiveIncomeLossRegulatoryAdjustmentForeignCurrencyTranslationNetOfTax"/>
    <loc xlink:type="locator" xlink:href="swx-20150930.xsd#swx_OtherComprehensiveIncomeLossRegulatoryAdjustmentForeignCurrencyTranslationTax" xlink:label="swx_OtherComprehensiveIncomeLossRegulatoryAdjustmentForeignCurrencyTranslationTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent" xlink:to="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" order="1.0700" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent" xlink:to="swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentBeforeTaxPortionAttributableToNoncontrollingInterest" order="1.0800" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:to="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" order="1.2500" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:to="swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest" order="1.2600" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansTaxPortionAttributableToParent" xlink:to="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" order="1.1600" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansTaxPortionAttributableToParent" xlink:to="swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentTaxPortionAttributableToNoncontrollingInterest" order="1.1700" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesBeforeTaxPortionAttributableToParent" xlink:to="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax" order="1.3200" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesBeforeTaxPortionAttributableToParent" xlink:to="swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentBeforeTaxPortionAttributableToNoncontrollingInterest" order="1.3300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPortionAttributableToParent" xlink:to="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax" order="1.4600" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPortionAttributableToParent" xlink:to="swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest" order="1.4700" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesTaxPortionAttributableToParent" xlink:to="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesTax" order="1.3900" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesTaxPortionAttributableToParent" xlink:to="swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentTaxPortionAttributableToNoncontrollingInterest" order="1.4000" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent" xlink:to="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentBeforeTax" order="1.5600" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent" xlink:to="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToNoncontrollingInterest" order="1.5700" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:to="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentNetOfTax" order="1.7600" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:to="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest" order="1.7700" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationAdjustmentTaxPortionAttributableToParent" xlink:to="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentTax" order="1.6600" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationAdjustmentTaxPortionAttributableToParent" xlink:to="us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationAdjustmentTaxPortionAttributableToNoncontrollingInterest" order="1.6700" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax" xlink:to="swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentBeforeTax" order="1.2900" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax" xlink:to="swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapsBeforeReclassificationAdjustmentsAndTax" order="1.3000" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax" order="1.3100" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax" xlink:to="swx_OtherComprehensiveIncomeLossForwardStartingInterestRateSwapForeignCurrencyTranslationAdjustmentNetOfTax" order="1.4300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax" xlink:to="swx_OtherComprehensiveIncomeLossDerivativesAdjustmentBeforeReclassificationAdjustmentsNetOfTax" order="1.4400" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax" order="1.4500" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesTax" xlink:to="swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentTax" order="1.3600" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesTax" xlink:to="swx_OtherComprehensiveIncomeLossDerivativesAdjustmentBeforeReclassificationAdjustmentsTax" order="1.3700" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax" order="1.3800" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentBeforeTax" xlink:to="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax" order="1.5100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentBeforeTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationBeforeTax" order="1.5200" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentBeforeTax" xlink:to="swx_OtherComprehensiveIncomeLossAmortizationOfPriorServiceCostForeignCurrencyTranslationAdjustmentBeforeTax" order="1.5300" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentBeforeTax" xlink:to="swx_OtherComprehensiveIncomeLossAmortizationOfNetActuarialLossForeignCurrencyTranslationAdjustmentBeforeTax" order="1.5400" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentBeforeTax" xlink:to="swx_OtherComprehensiveIncomeLossRegulatoryAdjustmentForeignCurrencyTranslationBeforeTax" order="1.5500" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" order="1.7100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationNetOfTax" order="1.7200" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentNetOfTax" xlink:to="swx_OtherComprehensiveIncomeLossAmortizationOfPriorServiceCostForeignCurrencyTranslationAdjustmentNetOfTax" order="1.7300" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentNetOfTax" xlink:to="swx_OtherComprehensiveIncomeLossAmortizationOfNetActuarialLossForeignCurrencyTranslationAdjustmentNetOfTax" order="1.7400" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentNetOfTax" xlink:to="swx_OtherComprehensiveIncomeLossRegulatoryAdjustmentForeignCurrencyTranslationNetOfTax" order="1.7500" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentTax" xlink:to="us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax" order="1.6100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationTax" order="1.6200" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentTax" xlink:to="swx_OtherComprehensiveIncomeLossAmortizationOfPriorServiceCostForeignCurrencyTranslationAdjustmentTax" order="1.6300" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentTax" xlink:to="swx_OtherComprehensiveIncomeLossAmortizationOfNetActuarialLossForeignCurrencyTranslationAdjustmentTax" order="1.6400" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="swx_OtherComprehensiveIncomeLossForeignCurrencyTransactionAdjustmentTax" xlink:to="swx_OtherComprehensiveIncomeLossRegulatoryAdjustmentForeignCurrencyTranslationTax" order="1.6500" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" order="1.8100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax" order="1.8200" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax" order="1.8300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax" order="1.8400" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="swx_DefinedBenefitPlanRegulatoryAdjustmentNetOfTaxAmount" order="1.8500" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:to="swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansForeignCurrencyTranslationAdjustmentBeforeTax" order="1.0200" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsAndTax" order="1.0300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax" order="1.0400" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax" order="1.0500" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:to="swx_DefinedBenefitPlanRegulatoryAdjustmentBeforeTax" order="1.0600" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsNetOfTax" order="1.2100" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax" order="1.2200" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax" order="1.2300" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:to="swx_DefinedBenefitPlanRegulatoryAdjustmentNetOfTaxAmount" order="1.2400" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBeforeReclassificationAdjustmentsTax" order="1.1200" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax" order="1.1300" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTax" order="1.1400" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:to="swx_DefinedBenefitPlanRegulatoryAdjustmentTaxExpenseOrBenefit" order="1.1500" weight="-1.00" priority="2" use="optional"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureEquityOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeAmountRecognizedBeforeIncomeTaxAssociatedWithDefinedBenefitPlansInAccumulatedOtherComprehensiveIncome">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:label="us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax" xlink:label="us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax" xlink:label="us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RegulatoryAssets" xlink:label="us-gaap_RegulatoryAssets"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:to="us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax" order="1.0100" weight="-1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:to="us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax" order="1.0200" weight="1.00" priority="2" use="optional"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:to="us-gaap_RegulatoryAssets" order="1.0300" weight="1.00" priority="2" use="optional"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureAcquisitionOfConstructionServicesBusinessesAdditionalInformation">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureConstructionServicesRedeemableNoncontrollingInterestsAdditionalInformation">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/DisclosureConstructionServicesRedeemableNoncontrollingInterestsSummaryOfRedeemableNoncontrollingInterest">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsOrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsOrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlockPolicies">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsOrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlockTables">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsNetPeriodicBenefitCostDisclosureTextBlock">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsNetPeriodicBenefitCostDisclosureTextBlockTables">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsSegmentReportingDisclosureTextBlock">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsSegmentReportingDisclosureTextBlockTables">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsDerivativesAndFairValueTextBlock">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsDerivativesAndFairValueTextBlockTables">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsCommonStockDisclosureTextBlock">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsLongTermDebtTextBlock">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsLongTermDebtTextBlockTables">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsStockholdersEquityNoteDisclosureTextBlock">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsStockholdersEquityNoteDisclosureTextBlockTables">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsBusinessCombinationDisclosureTextBlock">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsMinorityInterestDisclosureTextBlock">
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://www.swgas.com/taxonomy/role/NotesToFinancialStatementsMinorityInterestDisclosureTextBlockTables">
  </calculationLink>
</linkbase>
