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  <xs:element id="swx_SecuredRevolvingCreditAndTermLoanFacilityMember" abstract="true" name="SecuredRevolvingCreditAndTermLoanFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_GasPipeInventoryAndOperatingSuppliesMember" abstract="true" name="GasPipeInventoryAndOperatingSuppliesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_DeferredPurchasedGasCostsRecoveredOrRefundedPeriod" abstract="false" name="DeferredPurchasedGasCostsRecoveredOrRefundedPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="swx_NatureOfOperationsPolicyTextBlock" abstract="false" name="NatureOfOperationsPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="swx_AccumulatedDefinedBenefitPlansAdjustmentRegulartoryAdjustmentAttributabletoParentMember" abstract="true" name="AccumulatedDefinedBenefitPlansAdjustmentRegulartoryAdjustmentAttributabletoParentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_DebenturesNotesThreePointEightPercentageDueTwoThousandAndFortySixMember" abstract="true" name="DebenturesNotesThreePointEightPercentageDueTwoThousandAndFortySixMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestTax" abstract="false" name="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestTax" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_DeferredPurchasedGasCostsEstimatedIncrementalCosts" abstract="false" name="DeferredPurchasedGasCostsEstimatedIncrementalCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_RevenueRecognitionNumberOfContractsWithOriginalDurationMoreThanOneYear" abstract="false" name="RevenueRecognitionNumberOfContractsWithOriginalDurationMoreThanOneYear" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="swx_OtherPropertyAndInvestments" abstract="false" name="OtherPropertyAndInvestments" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_SignificantAccountingPoliciesLineItems" abstract="true" name="SignificantAccountingPoliciesLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="swx_DebenturesMediumTermNotesSixPointSevenSixPercentageSeriesDueTwoThousandAndTwentySevenMember" abstract="true" name="DebenturesMediumTermNotesSixPointSevenSixPercentageSeriesDueTwoThousandAndTwentySevenMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_BidContractMember" abstract="true" name="BidContractMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_UnitPricedContractsMember" abstract="true" name="UnitPricedContractsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_DeferredPurchasedGasCostsPipelineImbalanceCharges" abstract="false" name="DeferredPurchasedGasCostsPipelineImbalanceCharges" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_EquityShelfProgramMember" abstract="true" name="EquityShelfProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_OtherRevenue" abstract="false" name="OtherRevenue" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_DrumParentIncMember" abstract="true" name="DrumParentIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_MasterServicesAgreementMember" abstract="true" name="MasterServicesAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_DebenturesEightPercentageSeriesDueTwoThousandAndTwentySixMember" abstract="true" name="DebenturesEightPercentageSeriesDueTwoThousandAndTwentySixMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_SouthwestGasCorporationMember" abstract="true" name="SouthwestGasCorporationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_CommonStockWeightedAverageIssuePricePerShare" abstract="false" name="CommonStockWeightedAverageIssuePricePerShare" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="swx_NumberOfPerformanceShareUnitsGranted" abstract="false" name="NumberOfPerformanceShareUnitsGranted" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="swx_MovementInRedeemableNoncontrollingInterestRollForward" abstract="true" name="MovementInRedeemableNoncontrollingInterestRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="swx_ChangesInCustomerAdvancesInvestingActivities" abstract="false" name="ChangesInCustomerAdvancesInvestingActivities" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTaxOther" abstract="false" name="OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTaxOther" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_AdjustmentsToAdditionalPaidInCapitalContributionsFromParent" abstract="false" name="AdjustmentsToAdditionalPaidInCapitalContributionsFromParent" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_TransportationMember" abstract="true" name="TransportationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_ProceedsFromIssuanceOfCommonStockGross" abstract="false" name="ProceedsFromIssuanceOfCommonStockGross" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_DebenturesNotesThreePointEightSevenFivePercentageDueTwoThousandAndTwentyTwoMember" abstract="true" name="DebenturesNotesThreePointEightSevenFivePercentageDueTwoThousandAndTwentyTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_ScheduleOfCommonStockActivityTableTextBlock" abstract="false" name="ScheduleOfCommonStockActivityTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="swx_ResidentialMember" abstract="true" name="ResidentialMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_NaturalGasOperationsMember" abstract="true" name="NaturalGasOperationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_CommercialPaperProgramMember" abstract="true" name="CommercialPaperProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_DeferredPurchasedCostsPolicyTextBlock" abstract="false" name="DeferredPurchasedCostsPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="swx_DebenturesNotesSixPointOnePercentageDueTwoThousandAndFortyOneMember" abstract="true" name="DebenturesNotesSixPointOnePercentageDueTwoThousandAndFortyOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_UtilityInfrastructureServicesSegmentMember" abstract="true" name="UtilityInfrastructureServicesSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_DebenturesMember" abstract="true" name="DebenturesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_AlternativeRevenueProgramRevenuesDeferrals" abstract="false" name="AlternativeRevenueProgramRevenuesDeferrals" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_ScheduleOfRelatedTaxEffectsAllocatedToComponentsOfOtherComprehensiveIncomeLossTableTextBlock" abstract="false" name="ScheduleOfRelatedTaxEffectsAllocatedToComponentsOfOtherComprehensiveIncomeLossTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="swx_RestrictedStockUnitPlanAndManagementIncentivePlanMember" abstract="true" name="RestrictedStockUnitPlanAndManagementIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_RevolvingCreditFacilityAndCommercialPaperMember" abstract="true" name="RevolvingCreditFacilityAndCommercialPaperMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_BilledOnCompletedContractsAndContractsInProgressMember" abstract="true" name="BilledOnCompletedContractsAndContractsInProgressMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAmountRecognizedRegulatoryAssetsBeforeTax" abstract="false" name="DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAmountRecognizedRegulatoryAssetsBeforeTax" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_CenturiSecuredRevolvingCreditFacilityMember" abstract="true" name="CenturiSecuredRevolvingCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_ProceedsFromRepaymentsOfLinesOfCreditAndCommercialPaper" abstract="false" name="ProceedsFromRepaymentsOfLinesOfCreditAndCommercialPaper" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_MiscellaneousIncomeExpense" abstract="false" name="MiscellaneousIncomeExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_StockholdersEquityAttributableToParentTax" abstract="false" name="StockholdersEquityAttributableToParentTax" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_IndustrialOrOtherMember" abstract="true" name="IndustrialOrOtherMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_PrepaidAndOtherCurrentAssetsPolicyPolicyTextBlock" abstract="false" name="PrepaidAndOtherCurrentAssetsPolicyPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="swx_SignificantAccountingPoliciesTable" abstract="true" name="SignificantAccountingPoliciesTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="swx_DebtInstrumentCovenantRatioOfFundedDebtToTotalCapitalization" abstract="false" name="DebtInstrumentCovenantRatioOfFundedDebtToTotalCapitalization" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="swx_LineOfCreditFacilityWorkingCapitalPurposes" abstract="false" name="LineOfCreditFacilityWorkingCapitalPurposes" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_DebenturesNotesFourPointFifteenPercentageDueTwoThousandAndFortyNineMember" abstract="true" name="DebenturesNotesFourPointFifteenPercentageDueTwoThousandAndFortyNineMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_AccumulatedDefinedBenefitPlansAdjustmentPriorServiceCostAttributabletoParentMember" abstract="true" name="AccumulatedDefinedBenefitPlansAdjustmentPriorServiceCostAttributabletoParentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_LineOfCreditFacilityAmountClassifiedAsLongTermDebt" abstract="false" name="LineOfCreditFacilityAmountClassifiedAsLongTermDebt" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_DividendReinvestmentAndStockPurchasePlanMember" abstract="true" name="DividendReinvestmentAndStockPurchasePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_GasInfrastructureServicesMember" abstract="true" name="GasInfrastructureServicesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_LargeCommercialMember" abstract="true" name="LargeCommercialMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_A100MillionCreditFacilityMember" abstract="true" name="A100MillionCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_OtherReceivablesMember" abstract="true" name="OtherReceivablesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_VariableRateBondsTwoThousandAndThreeSeriesADueTwoThousandAndThirtyEightMember" abstract="true" name="VariableRateBondsTwoThousandAndThreeSeriesADueTwoThousandAndThirtyEightMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_CenturiTermLoanFacilityMember" abstract="true" name="CenturiTermLoanFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_AccountsReceivableForServicesTableTextBlock" abstract="false" name="AccountsReceivableForServicesTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="swx_CenturiOtherDebtObligationsMember" abstract="true" name="CenturiOtherDebtObligationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_A400MillionCreditFacilityMember" abstract="true" name="A400MillionCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_CenturiGroupInc.Member" abstract="true" name="CenturiGroupInc.Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_OtherInfrastructureServicesMember" abstract="true" name="OtherInfrastructureServicesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_DebenturesNotesTwoPointTwoPercentageDueTwoThousandAndThirtyMember" abstract="true" name="DebenturesNotesTwoPointTwoPercentageDueTwoThousandAndThirtyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_DebenturesNotesThreePointSevenPercentageDueTwoThousandAndTwentyEightMember" abstract="true" name="DebenturesNotesThreePointSevenPercentageDueTwoThousandAndTwentyEightMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_A250MillionTermLoanMember" abstract="true" name="A250MillionTermLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_DebenturesNotesFourPointEightSevenFivePercentageDueTwoThousandAndFortyThreeMember" abstract="true" name="DebenturesNotesFourPointEightSevenFivePercentageDueTwoThousandAndFortyThreeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_AccountsReceivableExtendingPeriod" abstract="false" name="AccountsReceivableExtendingPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="swx_OtherCurrentLiabilitiesPolicyPolicyTextBlock" abstract="false" name="OtherCurrentLiabilitiesPolicyPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="swx_SouthwestGasCreditFacilityMember" abstract="true" name="SouthwestGasCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_VariableRateBondsTwoThousandAndNineSeriesADueTwoThousandAndThirtyNineMember" abstract="true" name="VariableRateBondsTwoThousandAndNineSeriesADueTwoThousandAndThirtyNineMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_PropertyPlantEquipmentAndIntangibleAssetsGross" abstract="false" name="PropertyPlantEquipmentAndIntangibleAssetsGross" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_PublicUtilitiesPropertyPlantAndEquipmentGasPlant" abstract="false" name="PublicUtilitiesPropertyPlantAndEquipmentGasPlant" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_DebenturesMediumTermNotesSevenPointSevenEightPercentageSeriesDueTwoThousandAndTwentyTwoMember" abstract="true" name="DebenturesMediumTermNotesSevenPointSevenEightPercentageSeriesDueTwoThousandAndTwentyTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_IndustrialDevelopmentRevenueBondsMember" abstract="true" name="IndustrialDevelopmentRevenueBondsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_ElectricPowerInfrastructureServicesMember" abstract="true" name="ElectricPowerInfrastructureServicesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_DebtInstrumentUnamortizedDiscountAndDebtIssuanceCosts" abstract="false" name="DebtInstrumentUnamortizedDiscountAndDebtIssuanceCosts" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_SmallCommercialMember" abstract="true" name="SmallCommercialMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_OtherComprehensiveIncomeDefinedBenefitPlansRegulatoryAdjustmentNetOfTax" abstract="false" name="OtherComprehensiveIncomeDefinedBenefitPlansRegulatoryAdjustmentNetOfTax" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestBeforeTax" abstract="false" name="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestBeforeTax" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_VariableRateBondsTwoThousandAndEightSeriesADueTwoThousandAndThirtyEightMember" abstract="true" name="VariableRateBondsTwoThousandAndEightSeriesADueTwoThousandAndThirtyEightMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_DeferredIncomeTaxesAndUnamortizedInvestmentTaxCredits" abstract="false" name="DeferredIncomeTaxesAndUnamortizedInvestmentTaxCredits" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_LinetecServicesLLCMember" abstract="true" name="LinetecServicesLLCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_ScheduleOfInformationAboutReceivablesRevenueEarnedOnContractsInProgressInExcessOfBillingsAndAmountsBilledInExcessOfRevenueEarnedOnContractsTableTextBlock" abstract="false" name="ScheduleOfInformationAboutReceivablesRevenueEarnedOnContractsInProgressInExcessOfBillingsAndAmountsBilledInExcessOfRevenueEarnedOnContractsTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="swx_AccruedUtilityRevenue" abstract="false" name="AccruedUtilityRevenue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_DebenturesMediumTermNotesSevenPointNineTwoPercentageSeriesDueTwoThousandAndTwentySevenMember" abstract="true" name="DebenturesMediumTermNotesSevenPointNineTwoPercentageSeriesDueTwoThousandAndTwentySevenMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_SaleOfStockAmountOfCommonStockOfferedForSale" abstract="false" name="SaleOfStockAmountOfCommonStockOfferedForSale" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_VariableRateBondsTaxExemptSeriesADueTwoThousandAndTwentyEightMember" abstract="true" name="VariableRateBondsTaxExemptSeriesADueTwoThousandAndTwentyEightMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
