Downsview-Roding-CFB Water Hardness & Quality Report (2026)

Downsview-Roding-CFB (a north Toronto community centred on the former Canadian Forces Base Downsview site, now the developing Downsview Park area near Sheppard and Allen Road) receives its drinking water from the City of Toronto, drawing from Lake Ontario via the F.J. Horgan Water Treatment Plant on the eastern lakeshore. 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 238.5 mg/L (13.9 gpg) — classified as very hard by Health Canada, with TDS of 606 mg/L, consistent with Toronto's northwest distribution corridor.

Downsview-Roding-CFB's supply draws from Lake Ontario's western basin via the F.J. Horgan plant's deep intakes — where dissolved Silurian and Devonian carbonate minerals from the Great Lakes watershed maintain consistently elevated calcium concentrations. The northwest Toronto distribution sub-zone, serving the former CFB Downsview site and adjacent Roding neighbourhoods, measures the same very hard 238–239 mg/L characteristic of Toronto's north and west distribution zones. The elevated TDS of 606 mg/L reflects the combined carbonate and sulphate mineral load in this supply corridor.

At 238.5 mg/L, Downsview residents and new homeowners in the redeveloping Downsview Park district face persistent scale challenges — kettle descaling every one to two weeks is typical. Hot water tanks accumulate scale and benefit from annual inspection and flushing. The City of Toronto provides zone-specific water quality information and reports at toronto.ca/water, and residents in the area's newer planned communities are encouraged to consider whole-home softening given the very hard water characteristic of all north Toronto distribution zones.