Shawinigan Water Hardness & Quality Report (2026)

Shawinigan's drinking water is managed by Ville de Shawinigan, the historic hydroelectric city of the Mauricie region, drawing from the Rivière Saint-Maurice via the Shawinigan Water Treatment Plant. Water undergoes coagulation, sedimentation, filtration, UV disinfection, and chloramination, fully meeting the Guidelines for Canadian Drinking Water Quality (GCDWQ). Hardness measures 102 mg/L (6.0 gpg) — classified as moderately hard by Health Canada, reflecting the Saint-Maurice River's transition from the soft Laurentian Shield highlands to the more calcareous St. Lawrence Lowlands plain.

The Rivière Saint-Maurice originates in Laurentian Shield uplands north of Trois-Rivières, draining through the Mastigouche and Saint-Maurice highlands — predominantly Precambrian granite and gneiss terrain. As the river descends through the hydroelectric falls at Shawinigan and approaches the St. Lawrence Lowlands, it accumulates moderate dissolved calcium from calcareous glacial overburden and the emerging Ordovician limestone Lowlands plain. The 102 mg/L measured in Shawinigan reflects this transition zone — softer than Trois-Rivières (75 mg/L from batch 3) upstream but also moderate given the local hydroelectric water management that shapes the Saint-Maurice River's chemistry at Shawinigan.

At 102 mg/L, Shawinigan 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. Ville de Shawinigan publishes annual water quality reports following Ministère de l'Environnement standards; residents in Shawinigan's significant stock of early-twentieth-century industrial-era housing are encouraged to follow Health Canada lead precautionary guidance.