Mirabel Water Hardness & Quality Report (2026)

Mirabel's drinking water is managed by Ville de Mirabel, one of Quebec's geographically largest municipalities encompassing the Laurentian foothills north of Montréal (including the former Mirabel International Airport site), drawing from local river watershed sources via the municipal water treatment system. Water undergoes coagulation, sedimentation, filtration, UV disinfection, and chloramination, meeting all Guidelines for Canadian Drinking Water Quality (GCDWQ) requirements. Hardness measures 102.5 mg/L (6.0 gpg) — classified as moderately hard by Health Canada, reflecting the moderately calcareous character of the Laurentides–Lowlands transitional watershed.

Mirabel's sprawling territory spans the transition zone between the Precambrian Shield Laurentian hills to the north and the Ordovician limestone Lowlands plain to the south. River and groundwater sources in this transitional zone pick up dissolved calcium from calcareous glacial overburden deposited over the Lowlands limestone bedrock, producing the moderate 102.5 mg/L hardness — consistent with the broader Saint-Jérôme (73 mg/L), Blainville (70.5 mg/L), and Mirabel-area supply corridor values that characterise north shore municipalities at the Shield–Lowlands boundary.

At 102.5 mg/L, Mirabel residents experience moderate scale deposits in kettles and on tap aerators — descaling every six to eight weeks is adequate. Hot water tanks operate reliably at this hardness without dedicated treatment. Ville de Mirabel, covering an exceptionally large territory with diverse water infrastructure across its multiple urban sectors (Lachute, Saint-Janvier, Saint-Canut), provides water quality reports following Ministère de l'Environnement standards.