La Haute-Saint-Charles Water Hardness & Quality Report (2026)

La Haute-Saint-Charles (the northernmost borough of Ville de Québec, extending into the Laurentian foothills) receives its drinking water from Ville de Québec, drawing from the upper Rivière Saint-Charles watershed — primarily Lac Saint-Charles, a highland reservoir in the southern Laurentians northwest of the city — treated at the Québec Water Treatment Plant network. Treatment includes coagulation, sedimentation, ozonation, granular activated carbon filtration, and chlorination, fully meeting the Guidelines for Canadian Drinking Water Quality (GCDWQ). Hardness is 50.5 mg/L (2.9 gpg) — classified as soft by Health Canada, significantly softer than the downtown Québec boroughs (81–82 mg/L) due to the predominant Precambrian Shield source.

Lac Saint-Charles and the upper Rivière Saint-Charles watershed drain the Laurentian Plateau — a vast Precambrian Shield landscape of granite, gneiss, and anorthosite that extends northward from Québec City into the Laurentides region. This ancient crystalline bedrock dissolves almost no calcium or magnesium, yielding very soft, low-mineral water. La Haute-Saint-Charles draws from this soft Highland source, whereas the lower Québec City boroughs receive supply blended with harder St. Lawrence mainstream water — explaining the substantial hardness difference across the city's boroughs.

With 50.5 mg/L of hardness, La Haute-Saint-Charles residents enjoy minimal scale build-up on taps and appliances — occasional kettle descaling a few times per year is sufficient. Hot water tanks have an excellent lifespan at this hardness. However, the soft, mildly corrosive Shield water warrants periodic checking of pipe condition in older properties. Ville de Québec adjusts water chemistry for corrosivity throughout the distribution network and follows provincial Ministère de l'Environnement and Health Canada guidelines for all distribution water quality.