Hawkesbury Water Hardness & Quality Report (2026)

Hawkesbury's drinking water is managed by the Town of Hawkesbury, drawing from the Ottawa River in its lower reach — Hawkesbury is a bilingual (French-English) town in Prescott and Russell at the Ontario-Quebec border on the Ottawa River, directly across from Grenville, Quebec, one of the easternmost towns in Ontario before the Ottawa River joins the St. Lawrence system, with a strong Franco-Ontarian heritage and the L'Orignal county seat of Prescott and Russell nearby, home to the Hawkesbury General Hospital, the Hawkesbury-Grenville twin-city commercial corridor, and the historic Tronson-Calumet Island in the Ottawa River, the setting for the historic Calumet Bridge. Water undergoes coagulation, sedimentation, filtration, UV disinfection, and chloramination, fully meeting the Guidelines for Canadian Drinking Water Quality (GCDWQ). Hardness measures 185.5 mg/L (10.8 gpg) — classified as very hard by Health Canada, notably harder than the standard Ottawa River supply (116–120 mg/L from reference data).

Hawkesbury draws from the Ottawa River lower reach — at Hawkesbury, the Ottawa River is approaching its confluence with the St. Lawrence and has passed through the full length of the Ottawa-Outaouais carbonate lowlands, picking up dissolved minerals from the Ordovician limestone and dolomite formations of the lower Ottawa Valley, the Grenville carbonate transition, and the calcareous glacial drift of the eastern Ottawa Valley. At 185.5 mg/L and TDS 495.7 mg/L, this supply is significantly harder than the upper Ottawa River (Carleton Place 152.5 mg/L; The Glebe 91.5 mg/L from reference data), confirming the progressive carbonate dissolution increase along the Ottawa River course toward the St. Lawrence.

At 185.5 mg/L, Hawkesbury homeowners face persistent scale challenges — monthly to bimonthly kettle and showerhead descaling is typical. Hot water tanks benefit from periodic inspection. The Town of Hawkesbury provides water quality information at hawkesbury.ca. Health Canada lead precautionary guidance applies to pre-1975 properties in the historic Hawkesbury downtown heritage core on the Ottawa River.