Pembroke Water Hardness & Quality Report (2026)

Pembroke's drinking water is managed by the City of Pembroke, drawing from the Ottawa River in the upper Ottawa Valley — Pembroke is the county seat of Renfrew County, a mid-size city at the confluence of the Muskrat River and the Ottawa River in the heart of the Upper Ottawa Valley, the service and commercial hub for Renfrew County's logging and agricultural communities, and the gateway to Algonquin Park and the Madawaska Valley. Water undergoes coagulation, sedimentation, filtration, UV disinfection, and chloramination, meeting all Guidelines for Canadian Drinking Water Quality (GCDWQ) requirements. Hardness measures 149.5 mg/L (8.7 gpg) — classified as hard by Health Canada, reflecting the carbonate-transition character of the upper Ottawa River at Pembroke.

Pembroke's 149.5 mg/L occupies a transitional position along the Ottawa River hardness gradient — harder than the Ottawa city supply (116–120 mg/L from reference data) but softer than Petawawa (185.5 mg/L), with Pembroke between these two measurement points upstream along the Ottawa River. Moving up the Ottawa Valley toward the Renfrew–Pembroke–Petawawa corridor, the Ordovician and Cambrian carbonate bedrock of the Ottawa Valley lowlands gives way to the Precambrian carbonate-skarn and crystalline limestone contact zone, producing progressively harder water as the river draws from increasingly carbonate-influenced terrain.

At 149.5 mg/L, Pembroke homes experience regular scale deposits — monthly kettle and showerhead cleaning is typical. Hot water tanks benefit from periodic inspection and flushing. The City of Pembroke provides water quality information at pembroke.ca. Health Canada lead precautionary guidance applies to pre-1975 properties in the historic Pembroke townsite and the established residential streets above the Ottawa River valley.