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

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2021 Workiva-->
<!--r:9542a15e-921f-4def-a4d4-202f877ff5a2,g:4ac05ecf-0445-40e4-9677-f309e0c28324-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:pepl="http://www.energytransfer.com/20210331" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:nonnum="http://www.xbrl.org/dtr/type/non-numeric" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.energytransfer.com/20210331">
  <xs:import namespace="http://fasb.org/srt/2020-01-31" schemaLocation="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd"/>
  <xs:import namespace="http://fasb.org/us-gaap/2020-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd"/>
  <xs:import namespace="http://www.w3.org/1999/xlink" schemaLocation="http://www.xbrl.org/2003/xlink-2003-12-31.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/non-numeric" schemaLocation="http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.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/2020-01-31" schemaLocation="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.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="pepl-20210331_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="pepl-20210331_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" 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="pepl-20210331_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="pepl-20210331_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
      <link:roleType id="DocumentAndEntityInformation" roleURI="http://www.energytransfer.com/role/DocumentAndEntityInformation">
        <link:definition>0001001 - Document - Document And Entity Information</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="CONSOLIDATEDBALANCESHEETS" roleURI="http://www.energytransfer.com/role/CONSOLIDATEDBALANCESHEETS">
        <link:definition>1001002 - Statement - CONSOLIDATED BALANCE SHEETS</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="CONSOLIDATEDSTATEMENTSOFOPERATIONS" roleURI="http://www.energytransfer.com/role/CONSOLIDATEDSTATEMENTSOFOPERATIONS">
        <link:definition>1002003 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS</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="CONSOLIDATEDSTATEMENTOFPARTNERSCAPITAL" roleURI="http://www.energytransfer.com/role/CONSOLIDATEDSTATEMENTOFPARTNERSCAPITAL">
        <link:definition>1003004 - Statement - CONSOLIDATED STATEMENT OF PARTNERS' CAPITAL</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="CONSOLIDATEDSTATEMENTSOFCASHFLOWS" roleURI="http://www.energytransfer.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS">
        <link:definition>1004005 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS</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="OperationsandOrganizationNotes" roleURI="http://www.energytransfer.com/role/OperationsandOrganizationNotes">
        <link:definition>2101101 - Disclosure - Operations and Organization (Notes)</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="OPERATIONSANDORGANIZATIONPolicies" roleURI="http://www.energytransfer.com/role/OPERATIONSANDORGANIZATIONPolicies">
        <link:definition>2202201 - Disclosure - OPERATIONS AND ORGANIZATION (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="OPERATIONSANDORGANIZATIONTables" roleURI="http://www.energytransfer.com/role/OPERATIONSANDORGANIZATIONTables">
        <link:definition>2303301 - Disclosure - OPERATIONS AND ORGANIZATION (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="OperationsandOrganizationDetails" roleURI="http://www.energytransfer.com/role/OperationsandOrganizationDetails">
        <link:definition>2404401 - Disclosure - Operations and Organization (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="RelatedPartyTransactionsNotes" roleURI="http://www.energytransfer.com/role/RelatedPartyTransactionsNotes">
        <link:definition>2105102 - Disclosure - Related Party Transactions (Notes)</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="RelatedPartyTransactionsTables" roleURI="http://www.energytransfer.com/role/RelatedPartyTransactionsTables">
        <link:definition>2306302 - Disclosure - Related Party 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="RelatedPartyTransactionsDetails" roleURI="http://www.energytransfer.com/role/RelatedPartyTransactionsDetails">
        <link:definition>2407402 - Disclosure - Related Party Transactions (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="RelatedPartyNarrativeDetails" roleURI="http://www.energytransfer.com/role/RelatedPartyNarrativeDetails">
        <link:definition>2408403 - Disclosure - Related Party (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="FAIRVALUEMEASURESNotes" roleURI="http://www.energytransfer.com/role/FAIRVALUEMEASURESNotes">
        <link:definition>2109103 - Disclosure - FAIR VALUE MEASURES (Notes)</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="FAIRVALUEMEASURESDetails" roleURI="http://www.energytransfer.com/role/FAIRVALUEMEASURESDetails">
        <link:definition>2410404 - Disclosure - FAIR VALUE MEASURES (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="RegulatoryMattersCommitmentsContingenciesandEnvironmentalNotes" roleURI="http://www.energytransfer.com/role/RegulatoryMattersCommitmentsContingenciesandEnvironmentalNotes">
        <link:definition>2111104 - Disclosure - Regulatory Matters, Commitments, Contingencies and Environmental (Notes)</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="RegulatoryMattersCommitmentsContingenciesandEnvironmentalDetails" roleURI="http://www.energytransfer.com/role/RegulatoryMattersCommitmentsContingenciesandEnvironmentalDetails">
        <link:definition>2412405 - Disclosure - Regulatory Matters, Commitments, Contingencies and Environmental (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="pepl_ETOMember" abstract="true" name="ETOMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="pepl_IncomeStatementLineItems" abstract="true" name="IncomeStatementLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="pepl_ContingentResidualSupportAgreementMember" abstract="true" name="ContingentResidualSupportAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="pepl_IncomeStatementTable" abstract="true" name="IncomeStatementTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="pepl_AroAssetsDomain" abstract="true" name="AroAssetsDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="pepl_ContingentResidualSupportAgreementAmount" abstract="false" name="ContingentResidualSupportAgreementAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pepl_DescriptionOfBusinessLineItems" abstract="true" name="DescriptionOfBusinessLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="pepl_ExchangesPayable" abstract="false" name="ExchangesPayable" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pepl_AroAssetsAxis" abstract="true" name="AroAssetsAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="pepl_DocumentandEntityInformationAbstract" abstract="true" name="DocumentandEntityInformationAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="pepl_RegulatoryMattersCommitmentsContingenciesAndEnvironmentalLiabilitiesAbstract" abstract="true" name="RegulatoryMattersCommitmentsContingenciesAndEnvironmentalLiabilitiesAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="pepl_FINANCINGACTIVITIESAbstract" abstract="true" name="FINANCINGACTIVITIESAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="pepl_PanhandleMember" abstract="true" name="PanhandleMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="pepl_ExchangesReceivable" abstract="false" name="ExchangesReceivable" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pepl_OwnershipInterestTable" abstract="true" name="OwnershipInterestTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
</xs:schema>
