Middlesex Water Company

Middlesex Water Company

Middlesex Water Company

Middlesex Water Company (NASDAQ:MSEX) established in 1897, provides a full range of regulated and non-regulated water, wastewater utility and related services in parts of New Jersey and Delaware. Headquartered in Iselin, New Jersey, the company engages in collecting, treating, distributing and selling water for domestic, commercial, municipal, industrial and fire protection purposes.

Over a Century of Water Utility Expertise

Water Quality

Middlesex Water Company has a stringent water quality monitoring and testing program to ensure drinking water that meets and consistently exceeds state and federal water quality standards. The Company provides information on its water quality results to customers through Annual Water Quality Reports to customers.

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Middlesex System

Retail Customers

The Middlesex System in New Jersey provides water services to approximately 61,000 retail customers, primarily in eastern Middlesex County, New Jersey. Areas served on a retail basis include: The Township of Woodbridge, the city of South Amboy, the Boroughs of Carteret and Metuchen, portions of the Township of Edison and the Borough of South Plainfield and a small portion of the Township of Clark in Union County. These retail customers include a mix of residential customers, large industrial concerns, commercial and light industrial facilities.

Contract Customers

The Middlesex System also provides water under wholesale contracts to the City of Rahway, the Townships of Edison and Marlboro, the Boroughs of Highland Park and Sayreville and the Old Bridge Municipal Utilities Authority. Water treatment and pumping services are provided to the Township of East Brunswick under contract. Contract customers of the Middlesex System comprise an area of about 110 square miles with a population of approximately 219,000.  Contracts sales to Edison, Old Bridge, Marlboro and Rahway are supplemental to the existing water systems of these customers.

The Middlesex system utilizes both surface and groundwater supplies during various times of the year and customers may receive either or a blend of both sources depending upon location and demands. Surface water is obtained from the Delaware and Raritan Canal (D&R Canal), which is owned by the State of New Jersey and operated by the New Jersey Water Supply Authority. Surface water sources provide approximately 74 percent of the Middlesex system’s supply.  Groundwater sources provide approximately 19% of supply from 31 wells and the balance (7 percent) is purchased water from a non-affiliated water utility.

The Company obtains groundwater from its Wellfields in South Plainfield in North and South Edison. Groundwater comes from an underground source of water known as the Brunswick Aquifer. Middlesex Water’s rates are regulated by the New Jersey Board of Public Utilities. The Company is also subject to various Federal and State regulatory agencies concerning water quality standards.

Bayview System

Middlesex Water provides water service to approximately 300 customers in Cumberland County, NJ. This system is not physically interconnected with the Middlesex System. Water supply to Bayview system customers is derived solely from groundwater from an artesian aquifer known as the Lower Kirkwood Formation.

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Service Alerts

There are no service alerts at this time.

Contact Us

General Inquiries:


Water Service Emergency:

Contact us at (800) 549-3802 24/7, 365 days a year.

Hours of Operations:

Monday through Friday 9 AM-5 PM

Billing Inquiries:


Office Address:

Middlesex Water Company
1500 Ronson Road
Iselin, NJ 08830

Customer Service Address:

Middlesex Water Company
1500 Ronson Road
Iselin, NJ 08830