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  <xsd:element abstract="true" id="swx_DebenturesNotesThreePointEightPercentageDueTwoThousandAndFortySixMember" name="DebenturesNotesThreePointEightPercentageDueTwoThousandAndFortySixMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_DebenturesNotesThreePointEightSevenFivePercentageDueTwoThousandAndTwentyTwoMember" name="DebenturesNotesThreePointEightSevenFivePercentageDueTwoThousandAndTwentyTwoMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_DebenturesNotesThreePointSevenPercentageDueTwoThousandAndTwentyEightMember" name="DebenturesNotesThreePointSevenPercentageDueTwoThousandAndTwentyEightMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_DebtInstrumentCovenantComplianceCreditRiskExposureAmount" name="DebtInstrumentCovenantComplianceCreditRiskExposureAmount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="swx_DebtInstrumentDiscountRate" name="DebtInstrumentDiscountRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="swx_DebtInstrumentPercentageOfTotalWithInterestRatesReferenceToLIBORAndDueAfter2021" name="DebtInstrumentPercentageOfTotalWithInterestRatesReferenceToLIBORAndDueAfter2021" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="swx_DebtInstrumentUnamortizedDiscountAndDebtIssuanceCosts" name="DebtInstrumentUnamortizedDiscountAndDebtIssuanceCosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="swx_DefermentOfAnnualCashCompensation" name="DefermentOfAnnualCashCompensation" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_DeferredChargesAndOtherAssetsMember" name="DeferredChargesAndOtherAssetsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_DeferredCompensationArrangementWithIndividualMatchingPercentage" name="DeferredCompensationArrangementWithIndividualMatchingPercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_DeferredCompensationArrangementWithIndividualMaximumPercentageOfDeferral" name="DeferredCompensationArrangementWithIndividualMaximumPercentageOfDeferral" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_DeferredCompensationArrangementWithIndividualMaximumPercentageOfSalaryWithMatching" name="DeferredCompensationArrangementWithIndividualMaximumPercentageOfSalaryWithMatching" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_DeferredCompensationArrangementWithIndividualVestingPercentageOfDeferral" name="DeferredCompensationArrangementWithIndividualVestingPercentageOfDeferral" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_DeferredFederalAndStateIncomeTaxExpenseBenefit" name="DeferredFederalAndStateIncomeTaxExpenseBenefit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="swx_DeferredIncomeTaxesAndUnamortizedInvestmentTaxCredits" name="DeferredIncomeTaxesAndUnamortizedInvestmentTaxCredits" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="swx_DeferredInvestmentTaxCreditNet" name="DeferredInvestmentTaxCreditNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="swx_DeferredPurchasedCostsPolicyTextBlock" name="DeferredPurchasedCostsPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_DeferredPurchasedGasCostsAssetsMember" name="DeferredPurchasedGasCostsAssetsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_DeferredPurchasedGasCostsLiabilitiesMember" name="DeferredPurchasedGasCostsLiabilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_DeferredTaxAssetsLeaseRelatedItem" name="DeferredTaxAssetsLeaseRelatedItem" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="swx_DeferredTaxAssetsOperatingLossAndTaxCreditCarryforwardsNet" name="DeferredTaxAssetsOperatingLossAndTaxCreditCarryforwardsNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="swx_DeferredTaxLiabilitiesLeaseRelatedItem" name="DeferredTaxLiabilitiesLeaseRelatedItem" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="swx_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAmountRecognizedRegulatoryAssetsBeforeTax" name="DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAmountRecognizedRegulatoryAssetsBeforeTax" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="swx_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRateIncreaseDecrease" name="DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRateIncreaseDecrease" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRateIncrementsOfChange" name="DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRateIncrementsOfChange" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongtermRateofReturnonPlanAssetsIncreaseDecrease" name="DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongtermRateofReturnonPlanAssetsIncreaseDecrease" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_DefinedBenefitPlanPrivateCommingledFixedIncomeFundsMember" name="DefinedBenefitPlanPrivateCommingledFixedIncomeFundsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_DefinedBenefitPlanRegulatoryAdjustmentBeforeTaxNet" name="DefinedBenefitPlanRegulatoryAdjustmentBeforeTaxNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="swx_DerivativeCollateralOutstanding" name="DerivativeCollateralOutstanding" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="swx_DividendReinvestmentAndStockPurchasePlanMember" name="DividendReinvestmentAndStockPurchasePlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_EffectiveIncomeTaxRateReconciliationAmortizationOfExcessDeferredTaxesPercent" name="EffectiveIncomeTaxRateReconciliationAmortizationOfExcessDeferredTaxesPercent" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_EffectiveIncomeTaxRateReconciliationCompanyOwnedLifeInsurance" name="EffectiveIncomeTaxRateReconciliationCompanyOwnedLifeInsurance" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_ElectricPowerInfrastructureServicesMember" name="ElectricPowerInfrastructureServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_EmergingMarketsMember" name="EmergingMarketsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_EmployeeBenefitsMember" name="EmployeeBenefitsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_EmployeesInvestmentPlanCost" name="EmployeesInvestmentPlanCost" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_EnvironmentalComplianceProgramsMember" name="EnvironmentalComplianceProgramsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_EquityCushionRelatingToMinimumFixedChargeRatioCoverageRequirement" name="EquityCushionRelatingToMinimumFixedChargeRatioCoverageRequirement" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="swx_EquityCushionRelatingToMinimumNetWorthRequirement" name="EquityCushionRelatingToMinimumNetWorthRequirement" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_EquityShelfProgramMember" name="EquityShelfProgramMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_FinanceLeaseCost" name="FinanceLeaseCost" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="swx_FinanceLeasePrincipalPaymentsLeasesEnteredOrModifiedDuringPeriod" name="FinanceLeasePrincipalPaymentsLeasesEnteredOrModifiedDuringPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="swx_FloatingInterestRateIndex" name="FloatingInterestRateIndex" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_FutureEstimatedFundingAmount" name="FutureEstimatedFundingAmount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_GasInfrastructureServicesMember" name="GasInfrastructureServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_GasPipeInventoryAndOperatingSuppliesMember" name="GasPipeInventoryAndOperatingSuppliesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_GasUtilityCustomerAccountsReceivable" name="GasUtilityCustomerAccountsReceivable" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_GeneralMember" name="GeneralMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_GlobalMember" name="GlobalMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_GrossUpRelatedToContributionsInAidOfConstructionMember" name="GrossUpRelatedToContributionsInAidOfConstructionMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_IncomeTaxDisclosureLineItems" name="IncomeTaxDisclosureLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_IncomeTaxDisclosureTable" name="IncomeTaxDisclosureTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_IncomeTaxLineItems" name="IncomeTaxLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_IncomeTaxTable" name="IncomeTaxTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_IncomeTaxesLineItems" name="IncomeTaxesLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_IncomeTaxesPayableNet" name="IncomeTaxesPayableNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="swx_IncomeTaxesTable" name="IncomeTaxesTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_IndustrialDevelopmentRevenueBondsMember" name="IndustrialDevelopmentRevenueBondsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_IndustrialOrOtherMember" name="IndustrialOrOtherMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_InfrastructureReplacementProgramsAndSimilarMember" name="InfrastructureReplacementProgramsAndSimilarMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_InternationalMember" name="InternationalMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_LargeCommercialMember" name="LargeCommercialMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_LesseeOperatingLeaseRemainingLeaseTerm" name="LesseeOperatingLeaseRemainingLeaseTerm" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_LesseeOperatingLeaseTerminationPeriod" name="LesseeOperatingLeaseTerminationPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_LineOfCreditFacilityAmountClassifiedAsLongTermDebt" name="LineOfCreditFacilityAmountClassifiedAsLongTermDebt" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="swx_LineOfCreditFacilityMinimumAmountOutstandingDuringPeriod" name="LineOfCreditFacilityMinimumAmountOutstandingDuringPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="swx_LineOfCreditFacilityWorkingCapitalPurposes" name="LineOfCreditFacilityWorkingCapitalPurposes" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="swx_LinetecServicesLLCMember" name="LinetecServicesLLCMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_ManagementIncentivePlanMember" name="ManagementIncentivePlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_MarginInterestandPropertyTaxTrackingMember" name="MarginInterestandPropertyTaxTrackingMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_MasterServicesAgreementMember" name="MasterServicesAgreementMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_MatchingContributionOfEmployer" name="MatchingContributionOfEmployer" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_MaximumAggregateMarketValueOfPotentialStockIssuance" name="MaximumAggregateMarketValueOfPotentialStockIssuance" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="swx_MaximumAmountOfCommonStockAvailableForSale" name="MaximumAmountOfCommonStockAvailableForSale" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="swx_MiscellaneousIncomeExpense" name="MiscellaneousIncomeExpense" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_MovementInRedeemableNoncontrollingInterestRollForward" name="MovementInRedeemableNoncontrollingInterestRollForward" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_MultiemployerPlanNumberOfCriticalPlan" name="MultiemployerPlanNumberOfCriticalPlan" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="swx_MultiemployerPlanSpecialSurcharges" name="MultiemployerPlanSpecialSurcharges" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_NaturalGasOperationsMember" name="NaturalGasOperationsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_NatureOfOperationsPolicyTextBlock" name="NatureOfOperationsPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_NetRegulatoryLiabilities" name="NetRegulatoryLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="swx_NeucoMember" name="NeucoMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_NoncontrollingInterestPercentageOfInterestRetainedByNoncontrollingPartySubjectToElection" name="NoncontrollingInterestPercentageOfInterestRetainedByNoncontrollingPartySubjectToElection" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="swx_NumberOfCustomers" name="NumberOfCustomers" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_NumberOfCustomersPartyToContractsWithRateComponentsSubjectToNegotiation" name="NumberOfCustomersPartyToContractsWithRateComponentsSubjectToNegotiation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="swx_NumberOfPerformanceShareUnitsGranted" name="NumberOfPerformanceShareUnitsGranted" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_NumberOfTypesOfAgreementsWithCustomers" name="NumberOfTypesOfAgreementsWithCustomers" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_NumberOfTypesOfServicesProvidedToCustomers" name="NumberOfTypesOfServicesProvidedToCustomers" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_OperationsAndMaintenanceExpensePolicyTextBlock" name="OperationsAndMaintenanceExpensePolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_OtherComprehensiveIncomeDefinedBenefitPlansRegulatoryAdjustmentNetOfTax" name="OtherComprehensiveIncomeDefinedBenefitPlansRegulatoryAdjustmentNetOfTax" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="swx_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTaxOther" name="OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTaxOther" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="swx_OtherCurrentLiabilitiesPolicyTextBlock" name="OtherCurrentLiabilitiesPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_OtherDeferredCreditsAndOtherLongtermLiabilitiesMember" name="OtherDeferredCreditsAndOtherLongtermLiabilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_OtherDeferredCreditsMember" name="OtherDeferredCreditsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_OtherInfrastructureServicesMember" name="OtherInfrastructureServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_OtherMiscellaneousRegulatoryAssetMember" name="OtherMiscellaneousRegulatoryAssetMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_OtherMiscellaneousRegulatoryLiabilitiesMember" name="OtherMiscellaneousRegulatoryLiabilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_OtherPropertyAndInvestments" name="OtherPropertyAndInvestments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="swx_OtherRevenue" name="OtherRevenue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="swx_PaidAndReceivedFromCounterpartiesForSettlementsOfMaturedSwapsTableTextBlock" name="PaidAndReceivedFromCounterpartiesForSettlementsOfMaturedSwapsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_PaymentsForDerivativeInstrumentOperatingActivities" name="PaymentsForDerivativeInstrumentOperatingActivities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="swx_PercentOfCustomersByState" name="PercentOfCustomersByState" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_PercentageOfMaximumDividendPayoutRestriction" name="PercentageOfMaximumDividendPayoutRestriction" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_PooledFundsAndMutualFundsMember" name="PooledFundsAndMutualFundsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_PrepaidAndOtherCurrentAssetsPolicyPolicyTextBlock" name="PrepaidAndOtherCurrentAssetsPolicyPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_ProceedsFromIssuanceOfCommonStockGross" name="ProceedsFromIssuanceOfCommonStockGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="swx_ProceedsFromRepaymentsOfLinesOfCreditAndCommercialPaper" name="ProceedsFromRepaymentsOfLinesOfCreditAndCommercialPaper" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="swx_PropertyPlantEquipmentAndIntangibleAssetsGross" name="PropertyPlantEquipmentAndIntangibleAssetsGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="swx_PropertyRelatedItemsMember" name="PropertyRelatedItemsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_PublicUtilitiesAllowanceforFundsUsedDuringConstructionCapitalizedDebtPortion" name="PublicUtilitiesAllowanceforFundsUsedDuringConstructionCapitalizedDebtPortion" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="swx_PublicUtilitiesPropertyPlantandEquipmentGasPlant" name="PublicUtilitiesPropertyPlantandEquipmentGasPlant" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="swx_PurchasedGasCostAdjustmentsMember" name="PurchasedGasCostAdjustmentsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_ReceivablesAndRelatedAllowancesLineItems" name="ReceivablesAndRelatedAllowancesLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_ReceivablesAndRelatedAllowancesTable" name="ReceivablesAndRelatedAllowancesTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_RegulatoryAccountsForDifferencesRelatedToPensionFundingMember" name="RegulatoryAccountsForDifferencesRelatedToPensionFundingMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_RegulatoryAdjustmentsMember" name="RegulatoryAdjustmentsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_RegulatoryAssetsAndLiabilitiesLineItems" name="RegulatoryAssetsAndLiabilitiesLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_RegulatoryAssetsOtherMember" name="RegulatoryAssetsOtherMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_RegulatoryLiabilitiesOtherMember" name="RegulatoryLiabilitiesOtherMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_RegulatoryOffsetsToDeferredTaxBalancesMember" name="RegulatoryOffsetsToDeferredTaxBalancesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_ResidentialMember" name="ResidentialMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_RestrictedStockUnitPlanAndManagementIncentivePlanMember" name="RestrictedStockUnitPlanAndManagementIncentivePlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_RestrictedStockUnitPlanMember" name="RestrictedStockUnitPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_RevenueRecognitionNumberOfContractsWithOriginalDurationMoreThanOneYear" name="RevenueRecognitionNumberOfContractsWithOriginalDurationMoreThanOneYear" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="swx_RevolvingCreditFacilityAndCommercialPaperMember" name="RevolvingCreditFacilityAndCommercialPaperMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_ScheduleOfCommonStockActivityTableTextBlock" name="ScheduleOfCommonStockActivityTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_ScheduleOfConstructionServicesContractsReceivableTableTextBlock" name="ScheduleOfConstructionServicesContractsReceivableTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_ScheduleOfDeferredIncomeTaxExpenseBenefitTableTextBlock" name="ScheduleOfDeferredIncomeTaxExpenseBenefitTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_ScheduleOfDepreciationAndAmortizationExpenseTableTextBlock" name="ScheduleOfDepreciationAndAmortizationExpenseTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_ScheduleOfEffectiveInterestRatesOnLongTermDebtTableTextBlock" name="ScheduleOfEffectiveInterestRatesOnLongTermDebtTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_ScheduleOfEstimatedAmountsAmortizedFromAccumulatedOtherComprehensiveIncomeOrRegulatoryAssetsIntoNetPeriodicBenefitCostTableTextBlock" name="ScheduleOfEstimatedAmountsAmortizedFromAccumulatedOtherComprehensiveIncomeOrRegulatoryAssetsIntoNetPeriodicBenefitCostTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_ScheduleOfIncomeBeforeIncomeTaxContinuingAndDiscontinuedOperationsTableTextBlock" name="ScheduleOfIncomeBeforeIncomeTaxContinuingAndDiscontinuedOperationsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_ScheduleOfInformationAboutReceivablesRevenueEarnedOnContractsInProgressInExcessOfBillingsAndAmountsBilledInExcessOfRevenueEarnedOnContractsTableTextBlock" name="ScheduleOfInformationAboutReceivablesRevenueEarnedOnContractsInProgressInExcessOfBillingsAndAmountsBilledInExcessOfRevenueEarnedOnContractsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_ScheduleOfPercentOfCustomersByStateTableTextBlock" name="ScheduleOfPercentOfCustomersByStateTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_ScheduleOfQuarterlyFinancialInformationLineItems" name="ScheduleOfQuarterlyFinancialInformationLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_ScheduleOfQuarterlyFinancialInformationTable" name="ScheduleOfQuarterlyFinancialInformationTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_ScheduleOfRegulatoryAssetsAndLiabilitiesTable" name="ScheduleOfRegulatoryAssetsAndLiabilitiesTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_ScheduleOfRelatedTaxEffectsAllocatedToComponentsOfOtherComprehensiveIncomeLossTableTextBlock" name="ScheduleOfRelatedTaxEffectsAllocatedToComponentsOfOtherComprehensiveIncomeLossTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_SecuredRevolvingCreditFacilityTermLoanMember" name="SecuredRevolvingCreditFacilityTermLoanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_SelfInsuredRetentionAmountAssociatedWithGeneralLiabilityClaims" name="SelfInsuredRetentionAmountAssociatedWithGeneralLiabilityClaims" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="swx_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsDividends" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsDividends" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_SharebasedCompensationArrangementBySharebasedPaymentAwardNumberOfPlans" name="SharebasedCompensationArrangementBySharebasedPaymentAwardNumberOfPlans" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="swx_SharebasedCompensationArrangementbySharebasedPaymentAwardPerformanceMeasurementPeriod" name="SharebasedCompensationArrangementbySharebasedPaymentAwardPerformanceMeasurementPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_SignificantAccountingPoliciesLineItems" name="SignificantAccountingPoliciesLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_SignificantAccountingPoliciesTable" name="SignificantAccountingPoliciesTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_SignificantComponentsOfDeferredIncomeTaxExpenseLineItems" name="SignificantComponentsOfDeferredIncomeTaxExpenseLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_SignificantComponentsOfDeferredIncomeTaxExpenseTable" name="SignificantComponentsOfDeferredIncomeTaxExpenseTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_SmallCommercialMember" name="SmallCommercialMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_SouthwestGasCorporationMember" name="SouthwestGasCorporationMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_SouthwestGasCreditFacilityMember" name="SouthwestGasCreditFacilityMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_SouthwestMember" name="SouthwestMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_StateMandatedPublicPurposeProgramsMember" name="StateMandatedPublicPurposeProgramsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_StockholdersEquityAttributableToParentBeforeTax" name="StockholdersEquityAttributableToParentBeforeTax" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="swx_StockholdersEquityAttributableToParentTax" name="StockholdersEquityAttributableToParentTax" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="swx_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestBeforeTax" name="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestBeforeTax" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="swx_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestTax" name="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestTax" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="swx_StorageMember" name="StorageMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_TaxCutsAndJobsActOf2017RegulatoryLiability" name="TaxCutsAndJobsActOf2017RegulatoryLiability" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="swx_TaxReformSavingsRevenueAdjustmentsMember" name="TaxReformSavingsRevenueAdjustmentsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_TransportationMember" name="TransportationMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_UnamortizedGainOnReacquiredDebtMember" name="UnamortizedGainOnReacquiredDebtMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_UnamortizedPremiumOnReacquiredDebtMember" name="UnamortizedPremiumOnReacquiredDebtMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_UnitPricedContractsMember" name="UnitPricedContractsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_UnrealizedLossOnNonTradingDerivativesAssetsMember" name="UnrealizedLossOnNonTradingDerivativesAssetsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_UnrealizedLossOnNonTradingDerivativesLiabilitiesMember" name="UnrealizedLossOnNonTradingDerivativesLiabilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_UtilityInfrastructureServicesSegmentMember" name="UtilityInfrastructureServicesSegmentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="swx_UtilityPlantAndLeasesDisclosureTextBlock" name="UtilityPlantAndLeasesDisclosureTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_VariableRateBondsTaxExemptSeriesADueTwoThousandAndTwentyEightMember" name="VariableRateBondsTaxExemptSeriesADueTwoThousandAndTwentyEightMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_VariableRateBondsTwoThousandAndEightSeriesADueTwoThousandAndThirtyEightMember" name="VariableRateBondsTwoThousandAndEightSeriesADueTwoThousandAndThirtyEightMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_VariableRateBondsTwoThousandAndNineSeriesADueTwoThousandAndThirtyNineMember" name="VariableRateBondsTwoThousandAndNineSeriesADueTwoThousandAndThirtyNineMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_VariableRateBondsTwoThousandAndThreeSeriesADueTwoThousandAndThirtyEightMember" name="VariableRateBondsTwoThousandAndThreeSeriesADueTwoThousandAndThirtyEightMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="swx_WsNichollsWesternConstructionLtdMember" name="WsNichollsWesternConstructionLtdMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
</xsd:schema>
