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  <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://fasb.org/srt-types/2025" schemaLocation="https://xbrl.fasb.org/srt/2025/elts/srt-types-2025.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/sic/2025" schemaLocation="https://xbrl.sec.gov/sic/2025/sic-2025.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/ecd/2025" schemaLocation="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/ecd-sub/2025" schemaLocation="https://xbrl.sec.gov/ecd/2025/ecd-sub-2025.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/dei-sub/2025" schemaLocation="https://xbrl.sec.gov/dei/2025/dei-sub-2025.xsd"/>
  <xs:element name="ScheduleOfEarningsPerShareAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_ScheduleOfEarningsPerShareAbstract"/>
  <xs:element name="ScheduleOfSegmentTransactionsAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_ScheduleOfSegmentTransactionsAbstract"/>
  <xs:element name="ScheduleOfLinesOfCreditAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_ScheduleOfLinesOfCreditAbstract"/>
  <xs:element name="ScheduleOfEmployeeRetirementBenefitPlansAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_ScheduleOfEmployeeRetirementBenefitPlansAbstract"/>
  <xs:element name="ScheduleOfOperatingRevenuesAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_ScheduleOfOperatingRevenuesAbstract"/>
  <xs:element name="AverageNumberOfAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_AverageNumberOfAbstract"/>
  <xs:element name="UnlabeledAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_UnlabeledAbstract"/>
  <xs:element name="UnlabeledAbstract0" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_UnlabeledAbstract0"/>
  <xs:element name="CumulativePreferredStockNoParValueAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_CumulativePreferredStockNoParValueAbstract"/>
  <xs:element name="DilutedAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_DilutedAbstract"/>
  <xs:element name="DilutedAbstract0" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_DilutedAbstract0"/>
  <xs:element name="NonutilityAssetsNetNonCurrent" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="msex_NonutilityAssetsNetNonCurrent"/>
  <xs:element name="EmployeeBenefitPlans" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="msex_EmployeeBenefitPlans"/>
  <xs:element name="ConstructionAdvances" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="msex_ConstructionAdvances"/>
  <xs:element name="IncreaseDecreaseinUnbilledRevenues" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="msex_IncreaseDecreaseinUnbilledRevenues"/>
  <xs:element name="IncreaseDecreaseinRecoveredCostsEnvironmentalLitigationSettlement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="msex_IncreaseDecreaseinRecoveredCostsEnvironmentalLitigationSettlement"/>
  <xs:element name="PaymentsToAcquisitionOfWaterSystems" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="msex_PaymentsToAcquisitionOfWaterSystems"/>
  <xs:element name="AccruedPayablesForUtilityPlant" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="msex_AccruedPayablesForUtilityPlant"/>
  <xs:element name="EarningsPerShareScheduleofEarningsPerShareDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="msex_EarningsPerShareScheduleofEarningsPerShareDetailsTable"/>
  <xs:element name="NetIncomeAttributableToBasicEarningsPerShare" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_NetIncomeAttributableToBasicEarningsPerShare"/>
  <xs:element name="AdjustedEarningsApplicableToCommonStockDiluted" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="msex_AdjustedEarningsApplicableToCommonStockDiluted"/>
  <xs:element name="EarningsPerShareScheduleofEarningsPerShareParentheticalsDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="msex_EarningsPerShareScheduleofEarningsPerShareParentheticalsDetailsTable"/>
  <xs:element name="RenewalDateOfLineOfCredit" type="xbrli:dateItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_RenewalDateOfLineOfCredit"/>
  <xs:element name="CostOfTreatedWater" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="msex_CostOfTreatedWater"/>
  <xs:element name="CostOfUntreatedWater" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="msex_CostOfUntreatedWater"/>
  <xs:element name="RightOfUseAssetAtLeaseInception" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="msex_RightOfUseAssetAtLeaseInception"/>
  <xs:element name="OperatingLeaseRightOfUseAssetAccumulatedAmortization" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="msex_OperatingLeaseRightOfUseAssetAccumulatedAmortization"/>
  <xs:element name="EmployeeBenefitPlansScheduleofEmployeeRetirementBenefitPlansDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="msex_EmployeeBenefitPlansScheduleofEmployeeRetirementBenefitPlansDetailsTable"/>
  <xs:element name="OtherNonregulatedRevenues" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="msex_OtherNonregulatedRevenues"/>
  <xs:element name="InterSegmentEliminationOperatingRevenues" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="msex_InterSegmentEliminationOperatingRevenues"/>
  <xs:element name="BasisofPresentationandRecentDevelopmentsScheduleofRecentlyIssuedAccountingStandardsDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="msex_BasisofPresentationandRecentDevelopmentsScheduleofRecentlyIssuedAccountingStandardsDetailsTable"/>
  <xs:element name="BasisofPresentationandRecentDevelopmentsScheduleofRecentlyIssuedAccountingStandardsDetailsLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_BasisofPresentationandRecentDevelopmentsScheduleofRecentlyIssuedAccountingStandardsDetailsLineItems"/>
  <xs:element name="BasisofPresentationandRecentDevelopmentsDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="msex_BasisofPresentationandRecentDevelopmentsDetailsTable"/>
  <xs:element name="RateandRegulatoryMattersDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="msex_RateandRegulatoryMattersDetailsTable"/>
  <xs:element name="DistributionSystemImprovementChargeRate" type="dtr:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_DistributionSystemImprovementChargeRate"/>
  <xs:element name="PercentageOfConsumerPriceIndex" type="dtr:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_PercentageOfConsumerPriceIndex"/>
  <xs:element name="CapitalizationDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="msex_CapitalizationDetailsTable"/>
  <xs:element name="NetProceeds" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="msex_NetProceeds"/>
  <xs:element name="GrossSalesPrice" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="msex_GrossSalesPrice"/>
  <xs:element name="AdvancesForConstructionCarryingAmount" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="msex_AdvancesForConstructionCarryingAmount"/>
  <xs:element name="ShortTermBorrowingsDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="msex_ShortTermBorrowingsDetailsTable"/>
  <xs:element name="CommitmentsandContingentLiabilitiesDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="msex_CommitmentsandContingentLiabilitiesDetailsTable"/>
  <xs:element name="LongtermPurchaseCommitmentExpirationDate" type="xbrli:dateItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_LongtermPurchaseCommitmentExpirationDate"/>
  <xs:element name="AveragePurchaseOfGallons" type="dtr:volumeItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_AveragePurchaseOfGallons"/>
  <xs:element name="EstimatedIncrementalBorrowingRate" type="dtr:percentItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item" id="msex_EstimatedIncrementalBorrowingRate"/>
  <xs:element name="Estimatedobligationexpenditure" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="msex_Estimatedobligationexpenditure"/>
  <xs:element name="IncomeTaxesDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="msex_IncomeTaxesDetailsTable"/>
  <xs:element name="AmortizingSecuredNoteMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_AmortizingSecuredNoteMember"/>
  <xs:element name="AmortizingSecuredNotesDue20282046Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_AmortizingSecuredNotesDue20282046Member"/>
  <xs:element name="BankOfAmericaMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_BankOfAmericaMember"/>
  <xs:element name="CoBankACBMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_CoBankACBMember"/>
  <xs:element name="CommercialMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_CommercialMember"/>
  <xs:element name="CreditLinesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_CreditLinesMember"/>
  <xs:element name="DelawarePublicServiceCommissionMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_DelawarePublicServiceCommissionMember"/>
  <xs:element name="DelawareSRFLoansMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_DelawareSRFLoansMember"/>
  <xs:element name="FireProtectionMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_FireProtectionMember"/>
  <xs:element name="FirstMortgageBondsDue20262059Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_FirstMortgageBondsDue20262059Member"/>
  <xs:element name="FirstMortgageOne1Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_FirstMortgageOne1Member"/>
  <xs:element name="IndustrialMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_IndustrialMember"/>
  <xs:element name="InterSegmentEliminationMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_InterSegmentEliminationMember"/>
  <xs:element name="LeadServiceLineReplacementMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_LeadServiceLineReplacementMember"/>
  <xs:element name="NJBPURegulatedWaterMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_NJBPURegulatedWaterMember"/>
  <xs:element name="NewJerseyBoardOfPublicUtilitiesNJBPUMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_NewJerseyBoardOfPublicUtilitiesNJBPUMember"/>
  <xs:element name="NewJerseySRFProgramMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_NewJerseySRFProgramMember"/>
  <xs:element name="NonRegulatedMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_NonRegulatedMember"/>
  <xs:element name="NonredeemablePreferredStock1Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_NonredeemablePreferredStock1Member"/>
  <xs:element name="PncBankMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_PncBankMember"/>
  <xs:element name="RegulatedMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_RegulatedMember"/>
  <xs:element name="ResidentialMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_ResidentialMember"/>
  <xs:element name="StateRevolvingFundLoanMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_StateRevolvingFundLoanMember"/>
  <xs:element name="StateRevolvingTrustNotesDue20262044Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_StateRevolvingTrustNotesDue20262044Member"/>
  <xs:element name="StateRevolvingTrustNotesOneMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_StateRevolvingTrustNotesOneMember"/>
  <xs:element name="TidewaterMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_TidewaterMember"/>
  <xs:element name="TreatedWaterMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_TreatedWaterMember"/>
  <xs:element name="WaterSupplyMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_WaterSupplyMember"/>
  <xs:element name="WholesaleMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_WholesaleMember"/>
  <xs:element name="DocumentAndEntityInformationAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="msex_DocumentAndEntityInformationAbstract"/>
</xs:schema>
