Water filtration in Terrebonne

Terrebonne is fed by two distinct sources. Most of the territory, including La Plaine, receives water from the Mille Îles River treated by the Régie d'aqueduc intermunicipale des Moulins — a plant with a five-star rating from the Drinking Water Excellence Program. The Carrefour des Fleurs sector in Lachenaie is supplied instead from the L'Assomption River via Repentigny's plant.

The Régie's water is soft: 52 mg/L of CaCO₃ per its published analyses, roughly 3 grains per gallon. Little limescale, then — but how soft a water is has nothing to do with how pure it is.

The 2025 municipal report records three exceedances of the lead standard across 51 samples taken in July and August, each followed by compliant re-sampling. Lead never comes from the plant: it comes from the service connection or the building's plumbing. That's exactly the kind of contaminant a point-of-use barrier intercepts.