Fast Facts about the City’s Water Treatment Plants

F.J. Horgan Water Treatment Plant

  • Opened in 1979, it is Toronto’s newest water treatment plant, providing water to customers in the east end and Region of York
  • Produces approximately 20% of Toronto’s drinking water
  • Can produce 800 million litres daily
  • Named after Frank J. Horgan, Commissioner of Works for Metro Toronto from 1980 to 1989
  • Expanded in 2009 to be the first and only plant that uses ozone as the primary disinfectant to control pathogens, seasonal taste and odour
  • Features a green roof and 10-megawatt standby power plant to meet demand in the event of a power outage

Island Water Treatment Plant

  • Sits on the site of the City’s first water treatment plant built in the 1900s, which is no longer in service
  • Current plant was built in 1977 and is located on Centre Island
  • Produces approximately 20% of Toronto’s drinking water
  • Can produce 440 million litres each day
  • Cold, treated water passes through a heat exchanging system, which enables Enwave to cool buildings in the downtown core. When the Island WTP is out of service, then the R.C. Harris WTP services Enwave’s Deep Lake Water Cooling project. 

R.C. Harris Water Treatment Plant

  • Constructed in the 1930s and opened in 1941, it is the largest water treatment plant in Toronto
  • Produces approximately 30% of Toronto’s drinking water
  • Can produce 950 million litres daily
  • Named after Roland Caldwell Harris, Commissioner of Works from 1912 to his death in 1945
  • Dubbed “The Palace of Purification”, it is the largest collection of Art Deco buildings in Toronto
  • Is a national historic civil engineering site, designated historical building and has been featured in many film, fashion and TV shoots
  • Vehicle access at this water treatment plant is restricted to those conducting official City business. Public vehicles cannot enter or park at the site. Consider walking, biking or taking public transit if you’re planning a visit.

 R.L. Clark Water Treatment Plant

  • Opened on November 22, 1968 and is located in Toronto’s South Etobicoke
  • Originally called the Westerly Plant, was later named after Ross Leopold Clark, Commissioner of Works for Metropolitan Toronto from 1956 to 1979
  • Produces approximately 30% of Toronto’s drinking water
  • Can produce 615 million litres daily