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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019efb2c-0701-7b3d-99d4-da905f7c4dc1,g:b7a372bf-ead2-448b-a473-2d644cb36949-->
<link:linkbase 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" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="https://xbrl.org/2023/arcrole/summation-item" xlink:type="simple" xlink:href="https://www.xbrl.org/2023/calculation-1.1.xsd#summation-item"/>
  <link:roleRef roleURI="http://middlesexwater.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFINCOMEUnaudited" xlink:type="simple" xlink:href="msex-20260630.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFINCOMEUnaudited"/>
  <link:calculationLink xlink:role="http://middlesexwater.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFINCOMEUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019efb2c-07d0-7f70-ad3f-9a36d2b56823" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019efb2c-07d0-7eb8-b386-be3e8faee1e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_019efb2c-07d0-7f70-ad3f-9a36d2b56823" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019efb2c-07d0-7eb8-b386-be3e8faee1e1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019efb2c-07d0-73c4-b3f2-4531d89cff9e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_019efb2c-07d0-7f70-ad3f-9a36d2b56823" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019efb2c-07d0-73c4-b3f2-4531d89cff9e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019efb2c-07d0-7f75-870f-c06f5fbcf83e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019efb2c-07d0-7d84-8ff5-d28c39d53e94" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019efb2c-07d0-7f75-870f-c06f5fbcf83e" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019efb2c-07d0-7d84-8ff5-d28c39d53e94" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_019efb2c-07d0-7ed2-b095-96166c7f6c20" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpenses"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UtilitiesOperatingExpenseMaintenanceAndOperations_019efb2c-07d0-7291-8c18-a38bb61cbbb0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UtilitiesOperatingExpenseMaintenanceAndOperations"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_019efb2c-07d0-7ed2-b095-96166c7f6c20" xlink:to="loc_us-gaap_UtilitiesOperatingExpenseMaintenanceAndOperations_019efb2c-07d0-7291-8c18-a38bb61cbbb0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_019efb2c-07d0-75f5-ab28-b948e23db57b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Depreciation"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_019efb2c-07d0-7ed2-b095-96166c7f6c20" xlink:to="loc_us-gaap_Depreciation_019efb2c-07d0-75f5-ab28-b948e23db57b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxesOther_019efb2c-07d0-792c-bf4c-941a6b122b72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxesOther"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_019efb2c-07d0-7ed2-b095-96166c7f6c20" xlink:to="loc_us-gaap_TaxesOther_019efb2c-07d0-792c-bf4c-941a6b122b72" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_019efb2c-07d0-7a9d-8466-aab2f3751610" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionAdditions_019efb2c-07d0-75ee-8174-40e04d530705" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionAdditions"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_019efb2c-07d0-7a9d-8466-aab2f3751610" xlink:to="loc_us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionAdditions_019efb2c-07d0-75ee-8174-40e04d530705" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019efb2c-07d0-7226-bda5-c24230cb2c1f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_019efb2c-07d0-7a9d-8466-aab2f3751610" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019efb2c-07d0-7226-bda5-c24230cb2c1f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019efb2c-07d0-7377-bd1e-d9abf6861aed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019efb2c-07d0-77f9-8fa9-9fd612ba0f67" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019efb2c-07d0-7377-bd1e-d9abf6861aed" xlink:to="loc_us-gaap_NetIncomeLoss_019efb2c-07d0-77f9-8fa9-9fd612ba0f67" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_019efb2c-07d0-742f-b486-9f61f6fda0ad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockDividendsIncomeStatementImpact"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019efb2c-07d0-7377-bd1e-d9abf6861aed" xlink:to="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_019efb2c-07d0-742f-b486-9f61f6fda0ad" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019efb2c-07d0-76e7-b8ec-09a4af9403e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019efb2c-07d0-71f9-ad41-d0463f5f4729" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_019efb2c-07d0-76e7-b8ec-09a4af9403e5" xlink:to="loc_us-gaap_Revenues_019efb2c-07d0-71f9-ad41-d0463f5f4729" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_019efb2c-07d0-73b2-b5f9-115d54677c82" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpenses"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_019efb2c-07d0-76e7-b8ec-09a4af9403e5" xlink:to="loc_us-gaap_OperatingExpenses_019efb2c-07d0-73b2-b5f9-115d54677c82" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019efb2c-07d0-7f16-ac33-37f222a4dd7e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019efb2c-07d0-74b3-aba3-e4ac8b09a1cd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019efb2c-07d0-7f16-ac33-37f222a4dd7e" xlink:to="loc_us-gaap_OperatingIncomeLoss_019efb2c-07d0-74b3-aba3-e4ac8b09a1cd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_019efb2c-07d0-79d7-9d78-4ea32ff3adb2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019efb2c-07d0-7f16-ac33-37f222a4dd7e" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_019efb2c-07d0-79d7-9d78-4ea32ff3adb2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating_019efb2c-07d0-7914-927b-3415a8625f7e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019efb2c-07d0-7f16-ac33-37f222a4dd7e" xlink:to="loc_us-gaap_InterestExpenseNonoperating_019efb2c-07d0-7914-927b-3415a8625f7e" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://middlesexwater.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSUnaudited" xlink:type="simple" xlink:href="msex-20260630.xsd#CONDENSEDCONSOLIDATEDBALANCESHEETSUnaudited"/>
  <link:calculationLink xlink:role="http://middlesexwater.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_019efb2c-07d1-7afd-bcaf-320a97a84121" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_msex_NotesPayableCurrentExcludingCurrentMaturities_019efb2c-07d1-7489-8073-66f2a1d66572" xlink:href="msex-20260630.xsd#msex_NotesPayableCurrentExcludingCurrentMaturities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019efb2c-07d1-7afd-bcaf-320a97a84121" xlink:to="loc_msex_NotesPayableCurrentExcludingCurrentMaturities_019efb2c-07d1-7489-8073-66f2a1d66572" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_019efb2c-07d1-7cde-b6f0-64cf51d021c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019efb2c-07d1-7afd-bcaf-320a97a84121" xlink:to="loc_us-gaap_AccountsPayableCurrent_019efb2c-07d1-7cde-b6f0-64cf51d021c9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedIncomeTaxesCurrent_019efb2c-07d1-7d15-935f-a77f1da9934a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedIncomeTaxesCurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019efb2c-07d1-7afd-bcaf-320a97a84121" xlink:to="loc_us-gaap_AccruedIncomeTaxesCurrent_019efb2c-07d1-7d15-935f-a77f1da9934a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_019efb2c-07d1-7db7-81c6-ca5f54bf0324" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019efb2c-07d1-7afd-bcaf-320a97a84121" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_019efb2c-07d1-7db7-81c6-ca5f54bf0324" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019efb2c-07d1-74fa-a321-a8b7360aa75f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019efb2c-07d1-7afd-bcaf-320a97a84121" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019efb2c-07d1-74fa-a321-a8b7360aa75f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_019efb2c-07d1-7a2b-b9ca-a86cf0d3517a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019efb2c-07d1-7afd-bcaf-320a97a84121" xlink:to="loc_us-gaap_OtherLiabilitiesCurrent_019efb2c-07d1-7a2b-b9ca-a86cf0d3517a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_019efb2c-07d1-7f59-bdcc-a57ea7b218bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019efb2c-07d1-7afd-bcaf-320a97a84121" xlink:to="loc_us-gaap_LongTermDebtCurrent_019efb2c-07d1-7f59-bdcc-a57ea7b218bd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityCurrent_019efb2c-07d1-7453-8b6a-78d19700b189" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryLiabilityCurrent"/>
    <link:calculationArc order="8" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019efb2c-07d1-7afd-bcaf-320a97a84121" xlink:to="loc_us-gaap_RegulatoryLiabilityCurrent_019efb2c-07d1-7453-8b6a-78d19700b189" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizationLongtermDebtAndEquity_019efb2c-07d1-7407-b285-3270f311e72a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizationLongtermDebtAndEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapital_019efb2c-07d1-7b8e-8daa-547f490f8a77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnersCapital"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquity_019efb2c-07d1-7407-b285-3270f311e72a" xlink:to="loc_us-gaap_PartnersCapital_019efb2c-07d1-7b8e-8daa-547f490f8a77" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValue_019efb2c-07d1-7042-9639-4fbdd2fd39e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockValue"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquity_019efb2c-07d1-7407-b285-3270f311e72a" xlink:to="loc_us-gaap_PreferredStockValue_019efb2c-07d1-7042-9639-4fbdd2fd39e6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_019efb2c-07d1-7936-90f2-3792a7e9125a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquity_019efb2c-07d1-7407-b285-3270f311e72a" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_019efb2c-07d1-7936-90f2-3792a7e9125a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService_019efb2c-07d1-7a63-b976-9f247e38305c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentGenerationOrProcessing_019efb2c-07d1-7a93-abb6-ba43e1ecc97c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentGenerationOrProcessing"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService_019efb2c-07d1-7a63-b976-9f247e38305c" xlink:to="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentGenerationOrProcessing_019efb2c-07d1-7a93-abb6-ba43e1ecc97c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentTransmissionAndDistribution_019efb2c-07d1-7a2f-b910-c4e3346e6560" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentTransmissionAndDistribution"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService_019efb2c-07d1-7a63-b976-9f247e38305c" xlink:to="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentTransmissionAndDistribution_019efb2c-07d1-7a2f-b910-c4e3346e6560" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentCommon_019efb2c-07d1-74a1-90e9-beb3fc15a898" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentCommon"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService_019efb2c-07d1-7a63-b976-9f247e38305c" xlink:to="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentCommon_019efb2c-07d1-74a1-90e9-beb3fc15a898" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress_019efb2c-07d1-7724-a62a-3876ec781819" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService_019efb2c-07d1-7a63-b976-9f247e38305c" xlink:to="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress_019efb2c-07d1-7724-a62a-3876ec781819" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019efb2c-07d1-7e3c-89e0-863fdf92c1f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizationLongtermDebtAndEquity_019efb2c-07d1-79c5-bfb7-6b63766340a1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizationLongtermDebtAndEquity"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019efb2c-07d1-7e3c-89e0-863fdf92c1f5" xlink:to="loc_us-gaap_CapitalizationLongtermDebtAndEquity_019efb2c-07d1-79c5-bfb7-6b63766340a1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_019efb2c-07d1-729f-94f9-4fbae10658a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019efb2c-07d1-7e3c-89e0-863fdf92c1f5" xlink:to="loc_us-gaap_LiabilitiesCurrent_019efb2c-07d1-729f-94f9-4fbae10658a2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilities_019efb2c-07d1-796c-b04a-24c3941ae88a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilities"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019efb2c-07d1-7e3c-89e0-863fdf92c1f5" xlink:to="loc_us-gaap_OtherLiabilities_019efb2c-07d1-796c-b04a-24c3941ae88a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContributionsInAidOfConstruction_019efb2c-07d1-7a23-ba16-0fe37b9ecd07" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContributionsInAidOfConstruction"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019efb2c-07d1-7e3c-89e0-863fdf92c1f5" xlink:to="loc_us-gaap_ContributionsInAidOfConstruction_019efb2c-07d1-7a23-ba16-0fe37b9ecd07" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_019efb2c-07d1-75e2-935b-9028bbababa5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019efb2c-07d1-7e3c-89e0-863fdf92c1f5" xlink:to="loc_us-gaap_CommitmentsAndContingencies_019efb2c-07d1-75e2-935b-9028bbababa5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_019efb2c-07d1-7a99-ae7b-1b354e2f5b32" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019efb2c-07d1-757c-9891-8ace076fbce7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019efb2c-07d1-7a99-ae7b-1b354e2f5b32" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019efb2c-07d1-757c-9891-8ace076fbce7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_019efb2c-07d1-7921-896a-e933bfdba358" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019efb2c-07d1-7a99-ae7b-1b354e2f5b32" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_019efb2c-07d1-7921-896a-e933bfdba358" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnbilledReceivablesCurrent_019efb2c-07d1-7b01-b669-20ee8e6b2dbd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UnbilledReceivablesCurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019efb2c-07d1-7a99-ae7b-1b354e2f5b32" xlink:to="loc_us-gaap_UnbilledReceivablesCurrent_019efb2c-07d1-7b01-b669-20ee8e6b2dbd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryRawMaterialsAndSupplies_019efb2c-07d1-7631-88d2-50be49ed9722" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryRawMaterialsAndSupplies"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019efb2c-07d1-7a99-ae7b-1b354e2f5b32" xlink:to="loc_us-gaap_InventoryRawMaterialsAndSupplies_019efb2c-07d1-7631-88d2-50be49ed9722" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseCurrent_019efb2c-07d1-7dec-922d-378ac6555b84" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseCurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019efb2c-07d1-7a99-ae7b-1b354e2f5b32" xlink:to="loc_us-gaap_PrepaidExpenseCurrent_019efb2c-07d1-7dec-922d-378ac6555b84" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetsCurrent_019efb2c-07d1-78d4-995d-401615dbb3a0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryAssetsCurrent"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019efb2c-07d1-7a99-ae7b-1b354e2f5b32" xlink:to="loc_us-gaap_RegulatoryAssetsCurrent_019efb2c-07d1-78d4-995d-401615dbb3a0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019efb2c-07d1-71e1-864b-fc22a7d3b7a0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet_019efb2c-07d1-7752-bc6e-3a74d5f3cbab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019efb2c-07d1-71e1-864b-fc22a7d3b7a0" xlink:to="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet_019efb2c-07d1-7752-bc6e-3a74d5f3cbab" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_019efb2c-07d1-769d-8697-dfb326026809" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019efb2c-07d1-71e1-864b-fc22a7d3b7a0" xlink:to="loc_us-gaap_AssetsCurrent_019efb2c-07d1-769d-8697-dfb326026809" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssets_019efb2c-07d1-7c99-a947-2742943a8f1a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssets"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019efb2c-07d1-71e1-864b-fc22a7d3b7a0" xlink:to="loc_us-gaap_OtherAssets_019efb2c-07d1-7c99-a947-2742943a8f1a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssets_019efb2c-07d1-714c-b6a1-aa1761f6c5c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssets"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_019efb2c-07d1-724f-b5f5-f7c51167c36b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherAssets_019efb2c-07d1-714c-b6a1-aa1761f6c5c0" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_019efb2c-07d1-724f-b5f5-f7c51167c36b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashNoncurrent_019efb2c-07d1-7777-88c2-e0482ce17587" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashNoncurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherAssets_019efb2c-07d1-714c-b6a1-aa1761f6c5c0" xlink:to="loc_us-gaap_RestrictedCashNoncurrent_019efb2c-07d1-7777-88c2-e0482ce17587" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetsNoncurrent_019efb2c-07d1-7b38-afe4-703d598977cc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryAssetsNoncurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherAssets_019efb2c-07d1-714c-b6a1-aa1761f6c5c0" xlink:to="loc_us-gaap_RegulatoryAssetsNoncurrent_019efb2c-07d1-7b38-afe4-703d598977cc" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_msex_NonUtilityAssetsNetNoncurrent_019efb2c-07d1-737e-bee0-879461f5854e" xlink:href="msex-20260630.xsd#msex_NonUtilityAssetsNetNoncurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherAssets_019efb2c-07d1-714c-b6a1-aa1761f6c5c0" xlink:to="loc_msex_NonUtilityAssetsNetNoncurrent_019efb2c-07d1-737e-bee0-879461f5854e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_019efb2c-07d1-72ee-a76f-282b4394fab5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherAssets_019efb2c-07d1-714c-b6a1-aa1761f6c5c0" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_019efb2c-07d1-72ee-a76f-282b4394fab5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_msex_EmployeeBenefitPlans_019efb2c-07d1-7c58-8809-527ae82f3bd7" xlink:href="msex-20260630.xsd#msex_EmployeeBenefitPlans"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherAssets_019efb2c-07d1-714c-b6a1-aa1761f6c5c0" xlink:to="loc_msex_EmployeeBenefitPlans_019efb2c-07d1-7c58-8809-527ae82f3bd7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet_019efb2c-07d1-75c5-bc09-c924ebf98f14" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService_019efb2c-07d1-7203-ac0f-e999655b11fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet_019efb2c-07d1-75c5-bc09-c924ebf98f14" xlink:to="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService_019efb2c-07d1-7203-ac0f-e999655b11fb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation_019efb2c-07d1-720e-9d1c-5d3fc8129ba9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet_019efb2c-07d1-75c5-bc09-c924ebf98f14" xlink:to="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation_019efb2c-07d1-720e-9d1c-5d3fc8129ba9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilities_019efb2c-07d1-7394-b63b-6959eb59e5d5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionPayableCurrentAndNoncurrent_019efb2c-07d1-784f-bb85-1fcd2e2ee447" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionPayableCurrentAndNoncurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherLiabilities_019efb2c-07d1-7394-b63b-6959eb59e5d5" xlink:to="loc_us-gaap_ConstructionPayableCurrentAndNoncurrent_019efb2c-07d1-784f-bb85-1fcd2e2ee447" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_019efb2c-07d1-7c6c-8c4f-8a4ecf4cdc91" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherLiabilities_019efb2c-07d1-7394-b63b-6959eb59e5d5" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_019efb2c-07d1-7c6c-8c4f-8a4ecf4cdc91" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityNoncurrent_019efb2c-07d1-786b-8187-8fb30b5e6724" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryLiabilityNoncurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherLiabilities_019efb2c-07d1-7394-b63b-6959eb59e5d5" xlink:to="loc_us-gaap_RegulatoryLiabilityNoncurrent_019efb2c-07d1-786b-8187-8fb30b5e6724" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_019efb2c-07d1-76b9-bca8-7e5e0eec7d9e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherLiabilities_019efb2c-07d1-7394-b63b-6959eb59e5d5" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_019efb2c-07d1-76b9-bca8-7e5e0eec7d9e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_019efb2c-07d1-7781-9fcc-f9f6cad39243" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherLiabilities_019efb2c-07d1-7394-b63b-6959eb59e5d5" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_019efb2c-07d1-7781-9fcc-f9f6cad39243" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapital_019efb2c-07d1-7313-81ea-858fd10aa3d9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnersCapital"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_019efb2c-07d1-76fb-99d2-680202f203af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_PartnersCapital_019efb2c-07d1-7313-81ea-858fd10aa3d9" xlink:to="loc_us-gaap_CommonStockValue_019efb2c-07d1-76fb-99d2-680202f203af" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019efb2c-07d1-7e28-9231-2bad48a1222e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_PartnersCapital_019efb2c-07d1-7313-81ea-858fd10aa3d9" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019efb2c-07d1-7e28-9231-2bad48a1222e" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://middlesexwater.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWSUnaudited" xlink:type="simple" xlink:href="msex-20260630.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWSUnaudited"/>
  <link:calculationLink xlink:role="http://middlesexwater.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWSUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_019efb2c-07d1-7d68-985f-b0ecaea11019" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-7a40-957c-0c6096cea15a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_019efb2c-07d1-7d68-985f-b0ecaea11019" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-7a40-957c-0c6096cea15a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019efb2c-07d1-73aa-b95d-b555f48b9614" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_019efb2c-07d1-7d68-985f-b0ecaea11019" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019efb2c-07d1-73aa-b95d-b555f48b9614" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019efb2c-07d1-70d2-b8ec-a2816fd2b267" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_019efb2c-07d1-7d68-985f-b0ecaea11019" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019efb2c-07d1-70d2-b8ec-a2816fd2b267" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019efb2c-07d1-70e9-a30f-6ae40f38eaac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireWaterSystems_019f2100-e528-707e-a244-4abd7db3f9c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireWaterSystems"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019efb2c-07d1-70e9-a30f-6ae40f38eaac" xlink:to="loc_us-gaap_PaymentsToAcquireWaterSystems_019f2100-e528-707e-a244-4abd7db3f9c1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_msex_PaymentForUtilityPlantCapitalExpenditures_019efb2c-07d1-7193-9ce2-c8cd405792a8" xlink:href="msex-20260630.xsd#msex_PaymentForUtilityPlantCapitalExpenditures"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019efb2c-07d1-70e9-a30f-6ae40f38eaac" xlink:to="loc_msex_PaymentForUtilityPlantCapitalExpenditures_019efb2c-07d1-7193-9ce2-c8cd405792a8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019efb2c-07d1-7e39-aab1-1c3ef8486029" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_NetIncomeLoss_019efb2c-07d1-7e39-aab1-1c3ef8486029" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization_019efb2c-07d1-7aa3-8c80-b22c849924d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_DepreciationAndAmortization_019efb2c-07d1-7aa3-8c80-b22c849924d6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxesAndTaxCredits_019efb2c-07d1-7ac7-8531-1885c02b9f1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxesAndTaxCredits"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_DeferredIncomeTaxesAndTaxCredits_019efb2c-07d1-7ac7-8531-1885c02b9f1b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity_019efb2c-07d1-7623-972a-a974d7323650" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity_019efb2c-07d1-7623-972a-a974d7323650" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LifeInsuranceCorporateOrBankOwnedChangeInValue_019efb2c-07d1-7647-a0d8-72b960f1eb92" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LifeInsuranceCorporateOrBankOwnedChangeInValue"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_LifeInsuranceCorporateOrBankOwnedChangeInValue_019efb2c-07d1-7647-a0d8-72b960f1eb92" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_019efb2c-07d1-7981-bb85-5d1c1967e0cc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensation"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_ShareBasedCompensation_019efb2c-07d1-7981-bb85-5d1c1967e0cc" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_019efb2c-07d1-7de3-a4e0-bd9332368112" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <link:calculationArc order="7" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_019efb2c-07d1-7de3-a4e0-bd9332368112" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInContractWithCustomerAsset_019efb2c-07d1-7650-a3ee-62ee64892aee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerAsset"/>
    <link:calculationArc order="8" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_IncreaseDecreaseInContractWithCustomerAsset_019efb2c-07d1-7650-a3ee-62ee64892aee" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInRawMaterialsPackagingMaterialsAndSuppliesInventories_019efb2c-07d1-7c2e-b39a-e41b0639ce34" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInRawMaterialsPackagingMaterialsAndSuppliesInventories"/>
    <link:calculationArc order="9" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_IncreaseDecreaseInRawMaterialsPackagingMaterialsAndSuppliesInventories_019efb2c-07d1-7c2e-b39a-e41b0639ce34" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidExpense_019efb2c-07d1-7ba6-a951-8ad33f72fc77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInPrepaidExpense"/>
    <link:calculationArc order="10" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidExpense_019efb2c-07d1-7ba6-a951-8ad33f72fc77" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_019efb2c-07d1-72e0-b580-20d6ae407114" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <link:calculationArc order="11" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_019efb2c-07d1-72e0-b580-20d6ae407114" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedTaxesPayable_019efb2c-07d1-7ad0-940a-7a8569a65756" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccruedTaxesPayable"/>
    <link:calculationArc order="12" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedTaxesPayable_019efb2c-07d1-7ad0-940a-7a8569a65756" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_019efb2c-07d1-75c9-a299-2b94f2902be3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities"/>
    <link:calculationArc order="13" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_019efb2c-07d1-75c9-a299-2b94f2902be3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPensionAndPostretirementObligations_019efb2c-07d1-75b4-bf4f-d9fa9816c276" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInPensionAndPostretirementObligations"/>
    <link:calculationArc order="14" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_IncreaseDecreaseInPensionAndPostretirementObligations_019efb2c-07d1-75b4-bf4f-d9fa9816c276" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_019efb2c-07d1-73ed-90cf-f922b0f0775d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet"/>
    <link:calculationArc order="15" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019efb2c-07d1-762b-b6b8-18ef89935f2b" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_019efb2c-07d1-73ed-90cf-f922b0f0775d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019efb2c-07d1-71eb-a993-c5762228d97c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_019efb2c-07d1-7d9f-a0cd-8b0d22019f5d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfLongTermDebt"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019efb2c-07d1-71eb-a993-c5762228d97c" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_019efb2c-07d1-7d9f-a0cd-8b0d22019f5d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_019efb2c-07d1-76c3-8dff-12b7123c27eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019efb2c-07d1-71eb-a993-c5762228d97c" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_019efb2c-07d1-76c3-8dff-12b7123c27eb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromRepaymentsOfShortTermDebt_019efb2c-07d1-7918-bfde-251ca306577d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromRepaymentsOfShortTermDebt"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019efb2c-07d1-71eb-a993-c5762228d97c" xlink:to="loc_us-gaap_ProceedsFromRepaymentsOfShortTermDebt_019efb2c-07d1-7918-bfde-251ca306577d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDebtIssuanceCosts_019efb2c-07d1-7dc6-9a91-d048e61f2610" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfDebtIssuanceCosts"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019efb2c-07d1-71eb-a993-c5762228d97c" xlink:to="loc_us-gaap_PaymentsOfDebtIssuanceCosts_019efb2c-07d1-7dc6-9a91-d048e61f2610" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_019efb2c-07d1-7002-b376-3eaa29ce24a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019efb2c-07d1-71eb-a993-c5762228d97c" xlink:to="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_019efb2c-07d1-7002-b376-3eaa29ce24a2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_019efb2c-07d1-75e9-88c0-4c8d77d006c3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019efb2c-07d1-71eb-a993-c5762228d97c" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_019efb2c-07d1-75e9-88c0-4c8d77d006c3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts_019efb2c-07d1-76c3-a47e-5b6f07e28266" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfStockIssuanceCosts"/>
    <link:calculationArc order="7" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019efb2c-07d1-71eb-a993-c5762228d97c" xlink:to="loc_us-gaap_PaymentsOfStockIssuanceCosts_019efb2c-07d1-76c3-a47e-5b6f07e28266" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock_019efb2c-07d1-75c2-9893-91d31cb6427c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfDividendsCommonStock"/>
    <link:calculationArc order="8" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019efb2c-07d1-71eb-a993-c5762228d97c" xlink:to="loc_us-gaap_PaymentsOfDividendsCommonStock_019efb2c-07d1-75c2-9893-91d31cb6427c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock_019f3b5c-3382-75dc-824c-a49baaefbfc4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock"/>
    <link:calculationArc order="9" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019efb2c-07d1-71eb-a993-c5762228d97c" xlink:to="loc_us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock_019f3b5c-3382-75dc-824c-a49baaefbfc4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_019faf3b-df04-770f-bdbe-fe048f935efb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromPaymentsForOtherFinancingActivities"/>
    <link:calculationArc order="10" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019efb2c-07d1-71eb-a993-c5762228d97c" xlink:to="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_019faf3b-df04-770f-bdbe-fe048f935efb" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://middlesexwater.com/role/EarningsPerShareDetails" xlink:type="simple" xlink:href="msex-20260630.xsd#EarningsPerShareDetails"/>
  <link:calculationLink xlink:role="http://middlesexwater.com/role/EarningsPerShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_msex_NetIncomeLossAvailableToCommonStockholdersDilutedAdjusted_019efb2c-07d1-74c3-9903-58d099a6889a" xlink:href="msex-20260630.xsd#msex_NetIncomeLossAvailableToCommonStockholdersDilutedAdjusted"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019efb2c-07d1-76fa-b8c6-e7dc268e7831" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_msex_NetIncomeLossAvailableToCommonStockholdersDilutedAdjusted_019efb2c-07d1-74c3-9903-58d099a6889a" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019efb2c-07d1-76fa-b8c6-e7dc268e7831" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertiblePreferredDividendsNetOfTax_019efb2c-07d1-7e88-af7e-b490c803e208" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertiblePreferredDividendsNetOfTax"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_msex_NetIncomeLossAvailableToCommonStockholdersDilutedAdjusted_019efb2c-07d1-74c3-9903-58d099a6889a" xlink:to="loc_us-gaap_ConvertiblePreferredDividendsNetOfTax_019efb2c-07d1-7e88-af7e-b490c803e208" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019efb2c-07d1-7d50-bc15-54345e7af9d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019efb2c-07d1-701c-9fcb-7ec01b93f3db" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019efb2c-07d1-7d50-bc15-54345e7af9d8" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019efb2c-07d1-701c-9fcb-7ec01b93f3db" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToConversionOfPreferredStock_019efb2c-07d1-7e87-806c-5864c8c98823" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncrementalCommonSharesAttributableToConversionOfPreferredStock"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019efb2c-07d1-7d50-bc15-54345e7af9d8" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToConversionOfPreferredStock_019efb2c-07d1-7e87-806c-5864c8c98823" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://middlesexwater.com/role/CommitmentsandContingentLiabilitiesScheduleofPurchasedWaterCostsDetails" xlink:type="simple" xlink:href="msex-20260630.xsd#CommitmentsandContingentLiabilitiesScheduleofPurchasedWaterCostsDetails"/>
  <link:calculationLink xlink:role="http://middlesexwater.com/role/CommitmentsandContingentLiabilitiesScheduleofPurchasedWaterCostsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfPurchasedWater_019efb2c-08a1-724a-8269-41cb11cc0537" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfPurchasedWater"/>
    <link:loc xlink:type="locator" xlink:label="loc_msex_CostOfUntreatedWater_019efb2c-08a1-705d-a6ab-52519b4388ad" xlink:href="msex-20260630.xsd#msex_CostOfUntreatedWater"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CostOfPurchasedWater_019efb2c-08a1-724a-8269-41cb11cc0537" xlink:to="loc_msex_CostOfUntreatedWater_019efb2c-08a1-705d-a6ab-52519b4388ad" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_msex_CostOfTreatedWater_019efb2c-08a1-7669-84a0-2ac791bd580e" xlink:href="msex-20260630.xsd#msex_CostOfTreatedWater"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CostOfPurchasedWater_019efb2c-08a1-724a-8269-41cb11cc0537" xlink:to="loc_msex_CostOfTreatedWater_019efb2c-08a1-7669-84a0-2ac791bd580e" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://middlesexwater.com/role/EmployeeBenefitPlansScheduleofEmployeeRetirementBenefitPlansDetails" xlink:type="simple" xlink:href="msex-20260630.xsd#EmployeeBenefitPlansScheduleofEmployeeRetirementBenefitPlansDetails"/>
  <link:calculationLink xlink:role="http://middlesexwater.com/role/EmployeeBenefitPlansScheduleofEmployeeRetirementBenefitPlansDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019efb2c-08a1-7f82-8e5b-4737d4fa6d2f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost_019efb2c-08a1-7aa1-91fc-8a885bd75a52" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019efb2c-08a1-7f82-8e5b-4737d4fa6d2f" xlink:to="loc_us-gaap_DefinedBenefitPlanServiceCost_019efb2c-08a1-7aa1-91fc-8a885bd75a52" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_019efb2c-08a1-7048-8864-f95737f86729" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019efb2c-08a1-7f82-8e5b-4737d4fa6d2f" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_019efb2c-08a1-7048-8864-f95737f86729" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_019efb2c-08a1-7d9f-948d-3f5a85896354" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019efb2c-08a1-7f82-8e5b-4737d4fa6d2f" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_019efb2c-08a1-7d9f-948d-3f5a85896354" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_019efb2c-08a1-729e-9aa2-5ccea3a4c13a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019efb2c-08a1-7f82-8e5b-4737d4fa6d2f" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_019efb2c-08a1-729e-9aa2-5ccea3a4c13a" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://middlesexwater.com/role/RevenueRecognitionfromContractswithCustomersDetails" xlink:type="simple" xlink:href="msex-20260630.xsd#RevenueRecognitionfromContractswithCustomersDetails"/>
  <link:calculationLink xlink:role="http://middlesexwater.com/role/RevenueRecognitionfromContractswithCustomersDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019efb2c-08a1-733e-8686-0418489759fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019efb2c-08a1-7434-96e8-a5a22fe07868" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Revenues_019efb2c-08a1-733e-8686-0418489759fe" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019efb2c-08a1-7434-96e8-a5a22fe07868" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatedOperatingRevenueOther_019efb2c-08a1-7b63-88cf-b500ccbeca05" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatedOperatingRevenueOther"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Revenues_019efb2c-08a1-733e-8686-0418489759fe" xlink:to="loc_us-gaap_RegulatedOperatingRevenueOther_019efb2c-08a1-7b63-88cf-b500ccbeca05" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_msex_UnregulatedOperatingRevenueOther_019efb2c-08a1-7946-a01b-ed82b02e380d" xlink:href="msex-20260630.xsd#msex_UnregulatedOperatingRevenueOther"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Revenues_019efb2c-08a1-733e-8686-0418489759fe" xlink:to="loc_msex_UnregulatedOperatingRevenueOther_019efb2c-08a1-7946-a01b-ed82b02e380d" xlink:type="arc"/>
  </link:calculationLink>
</link:linkbase>
