High Park-Swansea Water Hardness & Quality Report (2026)

High Park-Swansea (a coveted west Toronto neighbourhood centred on the 399-acre High Park — Toronto's largest public park — and the historic village of Swansea along the Humber River inlet and Grenadier Pond, bordered by Bloor Street West, Roncesvalles, and the lake) receives its drinking water from the City of Toronto, drawing from Lake Ontario via the F.J. Horgan Water Treatment Plant. Water is treated using ozonation, biofiltration, UV disinfection, and chloramination, meeting all Guidelines for Canadian Drinking Water Quality (GCDWQ) standards. Hardness in this distribution zone is 242 mg/L (14.1 gpg) — classified as very hard by Health Canada, with TDS of 615 mg/L, consistent with the west Toronto and Etobicoke distribution corridor.

High Park-Swansea receives F.J. Horgan plant Lake Ontario supply through the west Toronto distribution network — part of the same characteristically very hard Lake Ontario source (dissolved Silurian and Devonian carbonate from the Great Lakes basin) that characterises all Toronto boroughs. The 242 mg/L is at the high end of Toronto's central distribution range, consistent with Stonegate-Queensway (240.5 mg/L) and Bay Street Corridor (240.5 mg/L) in the same western and downtown Toronto supply corridor.

At 242 mg/L, High Park-Swansea homeowners face persistent scale challenges in one of Toronto's most desirable and priciest neighbourhoods. Kettle and showerhead descaling every one to two weeks is typical. The community's large stock of heritage homes — many pre-1940 Swansea village properties along Ellis Avenue and Windermere — are subject to the City of Toronto's lead service line replacement programme. Residents are encouraged to review lead service line status at toronto.ca/water.