Montmagny Water Hardness & Quality Report (2026)

Montmagny's drinking water is managed by the Ville de Montmagny, drawing from the St. Lawrence River — Montmagny is the county seat of the Montmagny regional county municipality on the south shore of the St. Lawrence in the Chaudière-Appalaches administrative region, world-famous as the Capital of Snow Geese for the spectacular biannual migration of Greater Snow Geese through the Montmagny and Cap-Tourmente marshes — up to 1 million snow geese stop at the St. Lawrence estuary shores during fall (October) and spring (April) migrations, creating one of the most dramatic wildlife spectacles in North America. Water undergoes coagulation, sedimentation, filtration, UV disinfection, and chloramination, meeting all Guidelines for Canadian Drinking Water Quality (GCDWQ) requirements. Hardness measures 78.5 mg/L (4.6 gpg) — classified as moderately hard by Health Canada, consistent with the St. Lawrence south shore supply in the east Quebec City corridor.

Montmagny draws from the St. Lawrence River at the Chaudière-Appalaches south shore — at this point the St. Lawrence carries water mixed from the Great Lakes (carbonate-rich) and the Appalachian south shore tributaries (softer, Shield-influenced). The 78.5 mg/L reflects the blended St. Lawrence estuary supply in the Montmagny-Chaudière-Appalaches region, consistent with the transitional character of the St. Lawrence at this latitude between the urban Quebec City corridor (74–83.5 mg/L from reference data) and the more dilute lower St. Lawrence estuary. Water quality reports are published following Ministère de l'Environnement standards.

At 78.5 mg/L, Montmagny homes experience light scale deposits — cleaning every two months is adequate. Health Canada lead precautionary guidance applies to pre-1975 properties in the historic Montmagny townscape near the St. Lawrence waterfront.