Mount Pleasant West Water Hardness & Quality Report (2026)

Mount Pleasant West (a prosperous midtown Toronto neighbourhood north of Davisville and Yonge Street, extending up to Eglinton Avenue between Yonge and Bayview — home to the Leaside and Davisville corridor of single-family homes and mid-rise apartment buildings) receives its drinking water from the City of Toronto, drawing from Lake Ontario via the R.C. Harris 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 235.5 mg/L (13.8 gpg) — classified as very hard by Health Canada, with TDS of 593 mg/L, consistent with Toronto's midtown distribution corridor.

Mount Pleasant West receives R.C. Harris plant Lake Ontario supply through the north-central Toronto distribution network, sharing the fundamentally very hard Lake Ontario source (dissolved Silurian and Devonian carbonate from the Great Lakes basin) that characterises all Toronto boroughs. The 235.5 mg/L is consistent with the broader midtown Toronto range (233–240 mg/L) observed from Parkwoods-Donalda to Church-Yonge Corridor across the central and north-central supply zones.

At 235.5 mg/L, Mount Pleasant West homeowners face persistent scale challenges — kettle and showerhead descaling every one to two weeks is typical. Hot water tanks benefit from annual inspection and flushing in this established midtown neighbourhood. The area's significant stock of pre-1960 homes and post-war apartment buildings warrants attention to the City of Toronto's lead service line replacement programme at toronto.ca/water; residents in the neighbourhood's older heritage properties are encouraged to review lead service line status.