Trois-Rivières Water Hardness & Quality Report (2026)

The drinking water for Trois-Rivières, Quebec, is managed by the Ville de Trois-Rivières, supplying around 140,000 people throughout the city and nearby Mauricie areas. Its sole source is the Saint-Maurice River, with water drawn from the Pierre-Paul intake, located upstream from the city. The Station d'épuration des eaux Saint-Pie X treatment plant handles this raw river water, employing processes such as coagulation, flocculation, sedimentation, filtration, and chlorine disinfection. This system doesn't use any groundwater or reservoirs; it's entirely dependent on the river, without major connections to other water networks. The Saint-Maurice River watershed is vast, covering 43,000 square kilometers and draining the Laurentian Plateau within the Canadian Shield's Grenville Province.

The bedrock in this region is composed of ancient Precambrian granites, gneisses, and amphibolites, with very few carbonate rocks. This geological makeup prevents significant mineral dissolution, contributing to a soft water supply. The water has low cation content and minimal buffering capacity, further influenced by the surrounding coniferous forests and acidic sphagnum bogs that introduce organic acids. Glacial deposits of sand and gravel do form some minor unconfined aquifers, but the primary water supply comes directly from the river. This shield geology is the main reason for the water's softness.

Because this is a soft water supply, you'll find very little scale buildup, which is good news for your water heaters, pipes, and fixtures, as they're spared from limescale damage. Soap and detergents work very effectively, so you won't need to use extra amounts to overcome mineral interference. Appliances like dishwashers and washing machines should show minimal spotting or residue. A water softener isn't recommended here; instead, it's wise to monitor for corrosion in copper plumbing, as soft water can sometimes accelerate pipe wear if protective scaling is absent. The utility makes sure the water quality meets the Quebec Regulation respecting the quality of drinking water, typically maintaining a pH around 7.0-7.5 after treatment. They also manage lead and copper levels using corrosion control methods like pH adjustment and phosphate additions.