<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019efa46-6808-75f0-a92d-c662fb8740f6,g:888e99e2-7ac9-4eb9-916a-a9d95960ccd8-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:swx="http://www.southwestgas.com/20260625" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2024-01-31" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.southwestgas.com/20260625">
  <xs:import namespace="http://fasb.org/srt/2026" schemaLocation="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd"/>
  <xs:import namespace="http://fasb.org/us-gaap-ebp/2026" schemaLocation="https://xbrl.fasb.org/us-gaap/2026/ebp/elts/us-gaap-ebp-2026.xsd"/>
  <xs:import namespace="http://fasb.org/us-gaap/2026" schemaLocation="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd"/>
  <xs:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/dei/2026" schemaLocation="https://xbrl.sec.gov/dei/2026/dei-2026.xsd"/>
  <xs:annotation>
    <xs:appinfo>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="swx-20260625_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="swx-20260625_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="swx-20260625_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="swx-20260625_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple"/>
      <link:roleType id="Cover" roleURI="http://www.southwestgas.com/role/Cover">
        <link:definition>0000001 - Document - Cover</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StatementsofNetAssetsAvailableforBenefits" roleURI="http://www.southwestgas.com/role/StatementsofNetAssetsAvailableforBenefits">
        <link:definition>0000002 - Statement - Statements of Net Assets Available for Benefits</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StatementofChangesinNetAssetsAvailableforBenefits" roleURI="http://www.southwestgas.com/role/StatementofChangesinNetAssetsAvailableforBenefits">
        <link:definition>0000003 - Statement - Statement of Changes in Net Assets Available for Benefits</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DescriptionofthePlan" roleURI="http://www.southwestgas.com/role/DescriptionofthePlan">
        <link:definition>0000004 - Disclosure - Description of the Plan</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SummaryofAccountingPolicies" roleURI="http://www.southwestgas.com/role/SummaryofAccountingPolicies">
        <link:definition>0000005 - Disclosure - Summary of Accounting Policies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RelatedPartyandPartyInInterestTransactions" roleURI="http://www.southwestgas.com/role/RelatedPartyandPartyInInterestTransactions">
        <link:definition>0000006 - Disclosure - Related-Party and Party-In-Interest Transactions</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PlanTermination" roleURI="http://www.southwestgas.com/role/PlanTermination">
        <link:definition>0000007 - Disclosure - Plan Termination</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FederalIncomeTaxes" roleURI="http://www.southwestgas.com/role/FederalIncomeTaxes">
        <link:definition>0000008 - Disclosure - Federal Income Taxes</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurements" roleURI="http://www.southwestgas.com/role/FairValueMeasurements">
        <link:definition>0000009 - Disclosure - Fair Value Measurements</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SubsequentEvents" roleURI="http://www.southwestgas.com/role/SubsequentEvents">
        <link:definition>0000010 - Disclosure - Subsequent Events</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ScheduleHLine4iScheduleofAssetsHeldatEndofYear" roleURI="http://www.southwestgas.com/role/ScheduleHLine4iScheduleofAssetsHeldatEndofYear">
        <link:definition>0000011 - Disclosure - Schedule H, Line 4i &#8211; Schedule of Assets (Held at End of Year)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SummaryofAccountingPoliciesPolicies" roleURI="http://www.southwestgas.com/role/SummaryofAccountingPoliciesPolicies">
        <link:definition>0000012 - Disclosure - Summary of Accounting Policies (Policies)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DescriptionofthePlanTables" roleURI="http://www.southwestgas.com/role/DescriptionofthePlanTables">
        <link:definition>0000013 - Disclosure - Description of the Plan (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RelatedPartyandPartyInInterestTransactionsTables" roleURI="http://www.southwestgas.com/role/RelatedPartyandPartyInInterestTransactionsTables">
        <link:definition>0000014 - Disclosure - Related-Party and Party-In-Interest Transactions (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsTables" roleURI="http://www.southwestgas.com/role/FairValueMeasurementsTables">
        <link:definition>0000015 - Disclosure - Fair Value Measurements (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DescriptionofthePlanNarrativeDetails" roleURI="http://www.southwestgas.com/role/DescriptionofthePlanNarrativeDetails">
        <link:definition>0000016 - Disclosure - Description of the Plan - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DescriptionofthePlanScheduleofVestingPercentagesofEmployerContributionsDetails" roleURI="http://www.southwestgas.com/role/DescriptionofthePlanScheduleofVestingPercentagesofEmployerContributionsDetails">
        <link:definition>0000017 - Disclosure - Description of the Plan - Schedule of Vesting Percentages of Employer Contributions (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RelatedPartyandPartyInInterestTransactionsNarrativeDetails" roleURI="http://www.southwestgas.com/role/RelatedPartyandPartyInInterestTransactionsNarrativeDetails">
        <link:definition>0000018 - Disclosure - Related-Party and Party-In-Interest Transactions - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RelatedPartyandPartyInInterestTransactionsScheduleofInvestmentsHeldbyPartyInInterestDetails" roleURI="http://www.southwestgas.com/role/RelatedPartyandPartyInInterestTransactionsScheduleofInvestmentsHeldbyPartyInInterestDetails">
        <link:definition>0000019 - Disclosure - Related-Party and Party-In-Interest Transactions - Schedule of Investments Held by Party-In-Interest (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsScheduleofPlanAssetsAccountedatFairValueDetails" roleURI="http://www.southwestgas.com/role/FairValueMeasurementsScheduleofPlanAssetsAccountedatFairValueDetails">
        <link:definition>0000020 - Disclosure - Fair Value Measurements - Schedule of Plan Assets Accounted at Fair Value (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsScheduleofInvestmentsatNAVDetails" roleURI="http://www.southwestgas.com/role/FairValueMeasurementsScheduleofInvestmentsatNAVDetails">
        <link:definition>0000021 - Disclosure - Fair Value Measurements - Schedule of Investments at NAV (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsScheduleofInvestmentsatNAVDetails_1" roleURI="http://www.southwestgas.com/role/FairValueMeasurementsScheduleofInvestmentsatNAVDetails_1">
        <link:definition>0000021 - Disclosure - Fair Value Measurements - Schedule of Investments at NAV (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ScheduleHLine4iScheduleofAssetsHeldatEndofYearDetails" roleURI="http://www.southwestgas.com/role/ScheduleHLine4iScheduleofAssetsHeldatEndofYearDetails">
        <link:definition>0000022 - Disclosure - Schedule H, Line 4i &#8211; Schedule of Assets (Held at End of Year) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ScheduleHLine4iScheduleofAssetsHeldatEndofYearDetails_1" roleURI="http://www.southwestgas.com/role/ScheduleHLine4iScheduleofAssetsHeldatEndofYearDetails_1">
        <link:definition>0000022 - Disclosure - Schedule H, Line 4i &#8211; Schedule of Assets (Held at End of Year) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xs:appinfo>
  </xs:annotation>
  <xs:element id="swx_EBP004Member" abstract="true" name="EBP004Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPEmployerContributionParticipantsHireDateAxis" abstract="true" name="EBPEmployerContributionParticipantsHireDateAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="swx_EBPEmployerContributionParticipantsHireDateDomain" abstract="true" name="EBPEmployerContributionParticipantsHireDateDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPHiredPriorToJanuary12022Member" abstract="true" name="EBPHiredPriorToJanuary12022Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPHiredOnOrAfterJanuary12022Member" abstract="true" name="EBPHiredOnOrAfterJanuary12022Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPRetirementAgeDateAxis" abstract="true" name="EBPRetirementAgeDateAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="swx_EBPRetirementAgeDateDomain" abstract="true" name="EBPRetirementAgeDateDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPRetirementAgeOnOrAfterJanuary12020Member" abstract="true" name="EBPRetirementAgeOnOrAfterJanuary12020Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPRetirementAgePriorToJanuary12020Member" abstract="true" name="EBPRetirementAgePriorToJanuary12020Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPEmployerContributionTypeAxis" abstract="true" name="EBPEmployerContributionTypeAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="swx_EBPEmployerContributionTypeDomain" abstract="true" name="EBPEmployerContributionTypeDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPNonElectiveContributionMember" abstract="true" name="EBPNonElectiveContributionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPEmployerMatchingAndNonElectiveContributionMember" abstract="true" name="EBPEmployerMatchingAndNonElectiveContributionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPAutomaticPlanEnrollmentRequisitePeriod" abstract="false" name="EBPAutomaticPlanEnrollmentRequisitePeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="swx_EBPParticipantContributionMinimumAnnualCompensationToTotalCompensationPercentage" abstract="false" name="EBPParticipantContributionMinimumAnnualCompensationToTotalCompensationPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="swx_EBPParticipantContributionMaximumAnnualCompensationToTotalCompensationPercentage" abstract="false" name="EBPParticipantContributionMaximumAnnualCompensationToTotalCompensationPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="swx_EBPEmployerContributionMaximumVestingAge" abstract="false" name="EBPEmployerContributionMaximumVestingAge" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="swx_EBPAssetHeldForInvestmentParticipantLoanBasisSpreadOnVariableRate" abstract="false" name="EBPAssetHeldForInvestmentParticipantLoanBasisSpreadOnVariableRate" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="swx_BPNoteReceivableFromParticipantMaximumBorrowingTerm" abstract="false" name="BPNoteReceivableFromParticipantMaximumBorrowingTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="swx_EBPRetirementAge" abstract="false" name="EBPRetirementAge" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:decimalItemType"/>
  <xs:element id="swx_EBPIndividualRetirementAccountThresholdAmount" abstract="false" name="EBPIndividualRetirementAccountThresholdAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_EBPInvoluntaryCashOutLimit" abstract="false" name="EBPInvoluntaryCashOutLimit" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_EBPPaymentOfBenefitsInEventOfDeathOfParticipantPeriodToRequestPaymentByBeneficiary" abstract="false" name="EBPPaymentOfBenefitsInEventOfDeathOfParticipantPeriodToRequestPaymentByBeneficiary" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="swx_EBPEmployerContributionVestingServicePeriodAxis" abstract="true" name="EBPEmployerContributionVestingServicePeriodAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="swx_EBPEmployerContributionVestingServicePeriodDomain" abstract="true" name="EBPEmployerContributionVestingServicePeriodDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPVestingServicePeriodYearOneMember" abstract="true" name="EBPVestingServicePeriodYearOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPVestingServicePeriodYearTwoMember" abstract="true" name="EBPVestingServicePeriodYearTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPVestingServicePeriodYearThreeMember" abstract="true" name="EBPVestingServicePeriodYearThreeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPVestingServicePeriodYearFourMember" abstract="true" name="EBPVestingServicePeriodYearFourMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPVestingServicePeriodYearFiveAndThereafterMember" abstract="true" name="EBPVestingServicePeriodYearFiveAndThereafterMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPEmployerContributionVestingPercentage" abstract="false" name="EBPEmployerContributionVestingPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="swx_EBPEmployerCommonStockAndFidelityManagementTrustCompanyMember" abstract="true" name="EBPEmployerCommonStockAndFidelityManagementTrustCompanyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPFidelityManagementTrustCompanyMember" abstract="true" name="EBPFidelityManagementTrustCompanyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_TemporaryCashInvestmentsMember" abstract="true" name="TemporaryCashInvestmentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="swx_EBPFairValueInvestmentNAVUnfundedCommitmentAndRedemptionRestrictions" abstract="false" name="EBPFairValueInvestmentNAVUnfundedCommitmentAndRedemptionRestrictions" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="swx_EBPFairValueInvestmentNAVRedemptionFrequency" abstract="false" name="EBPFairValueInvestmentNAVRedemptionFrequency" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
</xs:schema>
