<?xml version="1.0" encoding="US-ASCII"?>
<!-- This schema was created by staff of the U.S. Securities and Exchange Commission. -->
<!-- Data and content created by government employees within the scope of their employment -->
<!-- are not subject to domestic copyright protection. 17 U.S.C. 105. -->
<xs:schema
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:link="http://www.xbrl.org/2003/linkbase"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:sbs-sbsef-com="http://xbrl.sec.gov/sbs-sbsef-com/2024"
targetNamespace="http://xbrl.sec.gov/sbs-sbsef-com/2024"
elementFormDefault="qualified"
xsi:schemaLocation="http://www.xbrl.org/2006/ref http://www.xbrl.org/2006/ref-2006-02-27.xsd">
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<link:roleRef roleURI="http://xbrl.sec.gov/sbsef/role/AffiliatesOnly" xlink:type="simple" xlink:href="sbs-2024.xsd#AffiliatesOnly"/>
<link:roleRef roleURI="http://xbrl.sec.gov/sbsef/role/Defaults" xlink:type="simple" xlink:href="sbs-2024.xsd#Defaults"/>
<link:roleRef roleURI="http://xbrl.sec.gov/sbsef/role/JurisdictionOnly" xlink:type="simple" xlink:href="sbs-2024.xsd#JurisdictionOnly"/>
<link:roleRef roleURI="http://xbrl.sec.gov/sbsef/role/RegulatorOnly" xlink:type="simple" xlink:href="sbs-2024.xsd#RegulatorOnly"/>
<link:presentationLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/sbsef/role/FileInformation">
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<link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="DocumentInformationLineItems" xlink:to="EntityRegistrantName" order="5.0" priority="10"/>
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<link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="DocumentInformationLineItems" xlink:to="EntityCentralIndexKey" order="6.0" priority="10"/>
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<link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="DocumentInformationLineItems" xlink:to="DocumentType" order="1.0" priority="10"/>
<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AmendmentFlag" xlink:label="AmendmentFlag"/>
<link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="DocumentInformationLineItems" xlink:to="AmendmentFlag" order="2.0" priority="10"/>
<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentPeriodEndDate" xlink:label="DocumentPeriodEndDate"/>
<link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="DocumentInformationLineItems" xlink:to="DocumentPeriodEndDate" order="4.0" priority="10"/>
<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AmendmentDescription" xlink:label="AmendmentDescription"/>
<link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="DocumentInformationLineItems" xlink:to="AmendmentDescription" order="3.0" priority="10"/>
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<link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/sbsef/role/AffiliatesOnly">
<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis"/>
<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain" xlink:label="EntityDomain"/>
<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" order="1.0" priority="10"/>
</link:definitionLink>
<link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/sbsef/role/JurisdictionOnly">
<link:loc xlink:type="locator" xlink:href="sbs-2024.xsd#sbs_SbsefJurisdictionAxis" xlink:label="SbsefJurisdictionAxis"/>
<link:loc xlink:type="locator" xlink:href="sbs-2024.xsd#sbs_SbsefJurisdictionDomain" xlink:label="SbsefJurisdictionDomain"/>
<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SbsefJurisdictionAxis" xlink:to="SbsefJurisdictionDomain" order="1.0" priority="10"/>
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<link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/sbsef/role/Defaults">
<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis"/>
<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain" xlink:label="EntityDomain"/>
<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" order="1.0" priority="10"/>
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<link:loc xlink:type="locator" xlink:href="sbs-2024.xsd#sbs_SbsefJurisdictionDomain" xlink:label="SbsefJurisdictionDomain"/>
<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SbsefJurisdictionAxis" xlink:to="SbsefJurisdictionDomain" order="1.0" priority="10"/>
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<link:loc xlink:type="locator" xlink:href="sbs-2024.xsd#sbs_SbsefRegulatorDomain" xlink:label="SbsefRegulatorDomain"/>
<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SbsefRegulatorAxis" xlink:to="SbsefRegulatorDomain" order="1.0" priority="10"/>
</link:definitionLink>
<link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/sbsef/role/RegulatorOnly">
<link:loc xlink:type="locator" xlink:href="sbs-2024.xsd#sbs_SbsefRegulatorAxis" xlink:label="SbsefRegulatorAxis"/>
<link:loc xlink:type="locator" xlink:href="sbs-2024.xsd#sbs_SbsefRegulatorDomain" xlink:label="SbsefRegulatorDomain"/>
<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SbsefRegulatorAxis" xlink:to="SbsefRegulatorDomain" order="1.0" priority="10"/>
</link:definitionLink>
<link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/sbsef/role/FileInformation">
<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentInformationLineItems" xlink:label="DocumentInformationLineItems"/>
<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentType" xlink:label="DocumentType"/>
<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="DocumentType" order="1.0" priority="10"/>
<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AmendmentFlag" xlink:label="AmendmentFlag"/>
<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="AmendmentFlag" order="2.0" priority="10"/>
<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AmendmentDescription" xlink:label="AmendmentDescription"/>
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<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentPeriodEndDate" xlink:label="DocumentPeriodEndDate"/>
<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="DocumentPeriodEndDate" order="4.0" priority="10"/>
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<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityRegistrantName" order="5.0" priority="10"/>
<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityCentralIndexKey" xlink:label="EntityCentralIndexKey"/>
<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityCentralIndexKey" order="6.0" priority="10"/>
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</xs:schema>
