Aylmer Water Hardness & Quality Report (2026)

Aylmer (a western sector of Ville de Gatineau on the Ontario–Québec border, overlooking the Ottawa River) receives its drinking water from Ville de Gatineau, drawing from the Ottawa River via the Aylmer Water Treatment Plant on the Gatineau south bank. Water undergoes coagulation, sedimentation, filtration, UV disinfection, and chloramination, fully meeting the Guidelines for Canadian Drinking Water Quality (GCDWQ). Hardness in Aylmer's distribution zone is 73.5 mg/L (4.3 gpg) — classified as moderately hard by Health Canada, notably softer than the Hull distribution zone (122.5 mg/L) in the same city, reflecting the proportionally greater Precambrian Shield tributary influence in the upper Ottawa River at Aylmer's intake.

Aylmer's intake on the Ottawa River is positioned further upstream (westward) than the Hull treatment plant, at a point where the river still carries a stronger proportion of soft Precambrian Shield tributary inflows from the Gatineau River highlands and the Laurentian Uplands. The Gatineau River — draining extensive granite and gneiss terrain north of Gatineau — contributes large volumes of very soft water to the Ottawa mainstream at this location, moderating the harder Ordovician limestone Lowlands baseline and producing the lower 73.5 mg/L measured in the Aylmer supply zone.

At 73.5 mg/L, Aylmer residents experience only moderate scale deposits in kettles and on tap aerators — descaling every two to three months is adequate. Hot water tanks operate reliably at this hardness. Ville de Gatineau produces annual water quality reports for the Aylmer and Hull distribution zones separately, following Ministère de l'Environnement provincial standards, and provides Health Canada-compliant lead guidance for residents in the borough's heritage housing and older residential properties.