MIDDLESEX WATER CO

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of

The Securities Exchange Act of 1934 (Amendment No. )

Filed by the Registrant ☒

Filed by a Party other than the Registrant ☐

Check the appropriate box:

☐ Preliminary Proxy Statement

☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

☒ Definitive Proxy Statement

☐ Definitive Additional Materials

☐ Soliciting Material Pursuant to §240.14a-12

Middlesex Water Company

(Name of Registrant as Specified in Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

☒ No fee required.

☐ Fee paid previously with preliminary materials.

☐ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11.

Middlesex Water Company485C Route 1 South Suite 400 Iselin, New Jersey 08830

Dear Valued Shareholders,

I am pleased to invite you to Middlesex Water Company’s Annual Meeting of Shareholders which will be conducted virtually on Tuesday, May 19, 2026 at 11:00 a.m. EDT. Over the past two years, I have had the privilege to serve as your President and Chief Executive officer and since 2025, as Chair of the Board.

During this period, our leadership team has worked with purpose and discipline to position Middlesex Water for long term success with the development and implementation of our MWC2030 vision. Your engagement and continued support are essential to our success and we value the opportunity to share our progress with you. For 2025, our operating and financial performance remained strong, driven by disciplined execution of our strategic priorities within each of our five pillars: Employee Engagement, Operational Excellence, Customer Experience, Stakeholder Management and Selective and Sustainable Growth. These results underscore the strength of our strategy and our commitment to delivering long-term value to our shareholders.

FINANCIAL HIGHLIGHTS

Our 2025 financial performance reflects the strength of our strategy and the stability of our regulated business model. The Company delivered solid net income of $42.8 million and revenue of $194.7 million while continuing our long-standing commitment to shareholder returns, marked by 53 consecutive years of dividend increases. Diluted earnings per share remained resilient at $2.36, supported by disciplined cost management and prudent capital allocation. We also expanded our regulated footprint, welcoming approximately 3,000 new customers into our company, further strengthening our foundation for sustainable growth.

STRATEGIC INFRASTRUCTURE INVESTMENT

Strategic investment in infrastructure remains at the core of our value proposition. In 2025, the company invested $96.4 million to upgrade, replace and enhance the resiliency of its water and wastewater utility infrastructure. In addition, from 2026 through 2028, we plan to invest approximately $506 million in infrastructure investments, which includes approximately $255 million to install treatment for Perfluoroalkyl Substances at our Carl J. Olsen surface water treatment plant in Edison, New Jersey.

As we look ahead, I want to express my sincere gratitude for your continued confidence in Middlesex Water Company. Your trust enables us to fulfill our mission of delivering safe, reliable, and life-sustaining water and wastewater services to the communities we are privileged to serve. We remain steadfast in our commitment to disciplined execution, long-term value creation, and responsible stewardship—today and for generations to come.

Sincerely,

Nadine Leslie

Chair, President and Chief Executive Officer

April 6, 2026

Table of Contents

Table of Contents

CONSERVING NATURAL RESOURCES THROUGH INTERNET AVAILABILITY OF PROXY MATERIALS

This year, we are again using the U.S. Securities and Exchange Commission’s Notice and Access model (“Notice and Access”) which allows delivery of proxy materials via the Internet as the primary means of furnishing proxy materials. We believe Notice and Access provides shareholders with a convenient method to access the proxy materials and vote, reduces the costs of printing and distributing proxy materials, and allows us to conserve natural resources in alignment with our role as an environmental steward.

On or about April 6, 2026, we will mail a Notice of Internet Availability (“NOIA”) of Proxy Materials containing instructions on how to access our Proxy Statement and our 2025 Annual Report online and how to vote via the Internet. The NOIA also contains instructions on how to receive a paper copy of the proxy materials and our 2025 Annual Report to Shareholders.

YOUR VOTE IS IMPORTANT

We urge you to vote using telephone or internet voting, if available to you, or if you received these proxy materials by U.S. mail, by completing, signing, dating and returning the enclosed proxy card promptly. If voting by phone, please call the toll-free number found on your NOIA of Proxy Materials or on your proxy card. To vote via the Internet, please visit the website shown on your NOIA (www.proxyvote.com) before 11:59 p.m. on May 18, 2026 to transmit voting instructions. (Shareholders will need the 12-digit control number from the proxy card or NOIA to view proxy materials atwww.proxyvote.com).

Shareholders of record may deliver their vote online during the virtual Annual Meeting by following directions on the Annual Meeting website. Beneficial owners of shares of common stock held in street name through a bank or brokerage account should follow the voting instructions enclosed with their proxy materials.