The Union Water Supply System (UWSS) is located in the south east quadrant of Essex County in Ontario. The system supplies treated water to the municipalities of Leamington, Kingsville and part of Essex and Lakeshore. It supplies water to a residential population of approximately 65,000 and a large number of commercial, industrial and agricultural customers. The business customers include several large food processors, and a large number of hydroponic greenhouses. The system is owned by the municipalities of Leamington, Kingsville, Essex and Lakeshore.

The UWSS has its origins in an Area Water System set up by the Ontario Water Resources Commission in 1959. The system was owned and operated by the Province until 2001. Under “The Municipal Water & Sewage Transfer Act, 1997” the ownership of the common system was formally transferred from the Province to the four municipalities. The transfer of all assets was completed in January 2001. The governance of the common system was given to the Joint Board of Management (the “Board”) of the Union Water Supply System. Each of the four municipalities nominates one or more municipal councillors to sit on the Board. The present Board has six Leamington representatives, four Kingsville representatives and one each from Essex and Lakeshore. In September 2002 the Board hired a General Manager who is responsible, among other things, for overseeing the operation, management and capital planning of the Union Water Supply System.

The UWSS owns one water treatment plant located in the hamlet of Ruthven in the Town of Kingsville. Raw water is taken from the western basin of Lake Erie through two offshore intakes. The water treatment plant has a rated capacity of 27.4 Million Imperial Gallons per day (124,590m3/day). There is a booster pumping station and in-ground reservoir in the hamlet of Cottam in Kingsville and elevated towers in Leamington, Essex and Kingsville. The UWSS contracts with The Ontario Clean Water Agency (OCWA) for operation of the plant and its associated facilities.

There are over 900 km of watermains within the UWSS service area. Local distribution of water within each of the 4 municipalities is handled by individual by local municipal water departments.