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<?xml version="1.0" encoding="windows-1252"?> |
<ownershipDocument> |
| <schemaVersion> X0508 </schemaVersion> |
| <documentType> 4 </documentType> |
| <periodOfReport> 2024-04-01 </periodOfReport> |
| <notSubjectToSection16> 0 </notSubjectToSection16> |
| <issuer> |
| | <issuerCik> 0000066004 </issuerCik> |
| | <issuerName> MIDDLESEX WATER CO </issuerName> |
| | <issuerTradingSymbol> MSEX </issuerTradingSymbol> |
| | </issuer> |
| <reportingOwner> |
| | <reportingOwnerId> |
| | | <rptOwnerCik> 0001185366 </rptOwnerCik> |
| | | <rptOwnerName> OCONNOR A BRUCE </rptOwnerName> |
| | | </reportingOwnerId> |
| | <reportingOwnerAddress> |
| | | <rptOwnerStreet1> 485C ROUTE 1 SOUTH </rptOwnerStreet1> |
| | | <rptOwnerStreet2> SUITE 400 </rptOwnerStreet2> |
| | | <rptOwnerCity> ISELIN </rptOwnerCity> |
| | | <rptOwnerState> NJ </rptOwnerState> |
| | | <rptOwnerZipCode> 08830 </rptOwnerZipCode> |
| | | <rptOwnerStateDescription></rptOwnerStateDescription> |
| | | </reportingOwnerAddress> |
| | <reportingOwnerRelationship> |
| | | <isDirector> 0 </isDirector> |
| | | <isOfficer> 1 </isOfficer> |
| | | <isTenPercentOwner> 0 </isTenPercentOwner> |
| | | <isOther> 0 </isOther> |
| | | <officerTitle> Sr. VP & CFO </officerTitle> |
| | | <otherText></otherText> |
| | | </reportingOwnerRelationship> |
| | </reportingOwner> |
| <aff10b5One> 0 </aff10b5One> |
| <nonDerivativeTable> |
| | <nonDerivativeTransaction> |
| | | <securityTitle> |
| <value> Common Stock (Restricted Stock Book Entry) </value> |
| </securityTitle> |
| | | <transactionDate> |
| <value> 2024-04-01 </value> |
| </transactionDate> |
| | | <deemedExecutionDate></deemedExecutionDate> |
| | | <transactionCoding> |
| <transactionFormType> 4 </transactionFormType> |
| <transactionCode> J </transactionCode> |
| <equitySwapInvolved> 0 </equitySwapInvolved> |
| </transactionCoding> |
| | | <transactionTimeliness></transactionTimeliness> |
| | | <transactionAmounts> |
| <transactionShares> |
| <value> 2848 </value> |
| <footnoteId id="F1"/> |
| </transactionShares> |
| <transactionPricePerShare> |
| <value> 52.50 </value> |
| </transactionPricePerShare> |
| <transactionAcquiredDisposedCode> |
| <value> D </value> |
| </transactionAcquiredDisposedCode> |
| </transactionAmounts> |
| | | <postTransactionAmounts> |
| <sharesOwnedFollowingTransaction> |
| <value> 8911 </value> |
| </sharesOwnedFollowingTransaction> |
| </postTransactionAmounts> |
| | | <ownershipNature> |
| <directOrIndirectOwnership> |
| <value> D </value> |
| </directOrIndirectOwnership> |
| </ownershipNature> |
| | | </nonDerivativeTransaction> |
| | <nonDerivativeTransaction> |
| | | <securityTitle> |
| <value> Common Stock - (Book Entry) </value> |
| </securityTitle> |
| | | <transactionDate> |
| <value> 2024-04-01 </value> |
| </transactionDate> |
| | | <deemedExecutionDate></deemedExecutionDate> |
| | | <transactionCoding> |
| <transactionFormType> 4 </transactionFormType> |
| <transactionCode> F </transactionCode> |
| <equitySwapInvolved> 0 </equitySwapInvolved> |
| </transactionCoding> |
| | | <transactionTimeliness></transactionTimeliness> |
| | | <transactionAmounts> |
| <transactionShares> |
| <value> 1399 </value> |
| <footnoteId id="F2"/> |
| </transactionShares> |
| <transactionPricePerShare> |
| <value> 52.50 </value> |
| </transactionPricePerShare> |
| <transactionAcquiredDisposedCode> |
| <value> A </value> |
| </transactionAcquiredDisposedCode> |
| </transactionAmounts> |
| | | <postTransactionAmounts> |
| <sharesOwnedFollowingTransaction> |
| <value> 19880 </value> |
| </sharesOwnedFollowingTransaction> |
| </postTransactionAmounts> |
| | | <ownershipNature> |
| <directOrIndirectOwnership> |
| <value> D </value> |
| </directOrIndirectOwnership> |
| </ownershipNature> |
| | | </nonDerivativeTransaction> |
| | <nonDerivativeHolding> |
| | | <securityTitle> |
| <value> Common Stock (DRP) </value> |
| </securityTitle> |
| | | <postTransactionAmounts> |
| <sharesOwnedFollowingTransaction> |
| <value> 0.5085 </value> |
| </sharesOwnedFollowingTransaction> |
| </postTransactionAmounts> |
| | | <ownershipNature> |
| <directOrIndirectOwnership> |
| <value> D </value> |
| </directOrIndirectOwnership> |
| </ownershipNature> |
| | | </nonDerivativeHolding> |
| | <nonDerivativeHolding> |
| | | <securityTitle> |
| <value> Common Stock (Street) </value> |
| </securityTitle> |
| | | <postTransactionAmounts> |
| <sharesOwnedFollowingTransaction> |
| <value> 2487 </value> |
| </sharesOwnedFollowingTransaction> |
| </postTransactionAmounts> |
| | | <ownershipNature> |
| <directOrIndirectOwnership> |
| <value> D </value> |
| </directOrIndirectOwnership> |
| </ownershipNature> |
| | | </nonDerivativeHolding> |
| | </nonDerivativeTable> |
| <footnotes> |
| | <footnote id="F1"> Represents the number of shares of Restricted Stock originally awarded that have now vested. </footnote> |
| | <footnote id="F2"> Represents the number of shares released to the awardee after choosing to surrender shares back to Issuer to satisfy the tax withholding obligations that arose in connection with the vesting of the Restricted Stock. </footnote> |
| | </footnotes> |
| <ownerSignature> |
| | <signatureName> s/Jay L. Kooper, Power of Attorney for A. Bruce O'Connor </signatureName> |
| | <signatureDate> 2024-04-03 </signatureDate> |
| | </ownerSignature> |
| </ownershipDocument> |