Company: MSEX
Filing Date: 2025-07-29
Form Type: 424B5
Source: 0001104659-25-071727
Chunk: 3

Company: MIDDLESEX WATER CO
Filing Date: 2025-07-29
Form: 424B5
Chunk 3
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 that there has been no change in the affairs of the Company
since the date of this prospectus supplement or that the information herein is correct as of any time subsequent to its date. This prospectus
supplement relates only to the Middlesex Common Stock offered hereby and is not to be relied upon in connection with the purchase or
sale of any other securities in the Company.

This Prospectus does not
constitute an offer to sell or a solicitation of an offer to buy shares of Middlesex Common Stock in any state or other jurisdiction
to any person to whom it is unlawful to make such an offer or solicitation.

<div align='center'>S-i

SUMMARY</div>

The following summary description
of the Middlesex Water Company Investment Plan (the “Plan”) is qualified by reference to the full text of the Plan which
appears in this prospectus supplement.

| · | If                                                                                               
 you do not currently own any shares of Middlesex Common Stock at all, you may join the Plan      
 by completing a Direct Share Purchase and Enrollment Form and either making an initial           
 investment of at least $500.00, up to a maximum of $10,000.00, or authorizing monthly deductions 
 of at least $25.00 from a qualified bank account for the purchase of Middlesex Common Stock.     |

| · | If                                                                                          
 you currently own at least one share of Middlesex Common Stock registered in your name, you 
 may participate in the Plan by simply completing and returning a Direct Share Purchase and  
 Enrollment form.                                                                            |

| · | Once                                                                                               
 you have enrolled, you may purchase additional shares of Middlesex Common Stock through additional 
 optional cash payments of $25.00 or more (maximum $25,000.00 per calendar quarter).                |

| · | You                                                                                        
 may purchase in dollar amounts, rather than a certain number of shares of Middlesex Common 
 Stock, so you can own fractional shares.                                                   |

| · | You                                                                                             
 may choose to buy additional Middlesex Common Stock with automatic monthly deductions from      
 your bank account or by check. Eligible employees of the Company (and its subsidiary companies) 
 have the additional option of utilizing automatic payroll deductions to purchase shares of      
 Middlesex Common Stock.                                                                         |

| · | As                                                                                                
 a participant, you may (but are not required to) deposit your Middlesex Common Stock certificates 
 with Broadridge Corporate Issuer Solutions, Inc. (the “Plan Agent”) for                           
 safekeeping.                                                                                      |