Les Coteaux Water Hardness & Quality Report (2026)

Les Coteaux's drinking water is managed by Municipalité de Les Coteaux, drawing from the Ottawa River or a local river source in the southwestern Montérégie corridor near the Ontario-Quebec border — Les Coteaux is a suburban municipality in the Vaudreuil-Soulanges sub-region, west of Vaudreuil-Dorion at the southwestern tip of Quebec near the point where the Ottawa River meets the St. Lawrence, in the heart of Quebec's growing southwest commuter belt. Water undergoes coagulation, sedimentation, filtration, UV disinfection, and chloramination, meeting all Guidelines for Canadian Drinking Water Quality (GCDWQ) requirements. Hardness measures 69.5 mg/L (4.1 gpg) — classified as moderately hard by Health Canada, consistent with the moderately soft Ottawa River supply character in the southwest Quebec corridor.

Les Coteaux's 69.5 mg/L is consistent with the Ottawa River supply in the lower Outaouais valley — at the point where the Ottawa River enters the St. Lawrence confluence area, the river's hardness (60–75 mg/L) reflects its long journey through the Precambrian Shield of eastern Ontario and western Quebec, carrying moderately mineralised water from the mixed Shield and lowland sedimentary terrain. The low TDS of 111.8 mg/L confirms the relatively lightly mineralised character of this southwest Quebec border supply.

At 69.5 mg/L, Les Coteaux homes experience light scale deposits — occasional kettle cleaning every two months is adequate. Hot water tanks have a good operational lifespan. Water quality reports are published following Ministère de l'Environnement standards. Health Canada lead precautionary guidance applies to pre-1975 residential properties in the municipality's established suburban neighbourhoods along the Chemin du Fleuve riverfront corridor.