Sept-Îles Water Hardness & Quality Report (2026)

Sept-Îles' drinking water is managed by Ville de Sept-Îles, the largest city of Quebec's Côte-Nord region, drawing from local rivers or watershed reservoirs on the North Shore draining the Precambrian Shield highlands. Water undergoes coagulation, sedimentation, filtration, UV disinfection, and chloramination, fully meeting the Guidelines for Canadian Drinking Water Quality (GCDWQ). Hardness measures 41 mg/L (2.4 gpg) — classified as soft by Health Canada, characteristic of the Quebec North Shore's Grenville Province Precambrian Shield terrain.

Sept-Îles is located on the Gulf of St. Lawrence north shore in the heart of the Grenville Province — a terrane of ancient Precambrian granite, anorthosite, and gneiss making up the Quebec North Shore bedrock, which is among the most insoluble geological material in Canada. River water draining through this crystalline basement picks up virtually no dissolved calcium, producing the very soft supply characteristic of all Côte-Nord municipalities. The 41 mg/L is consistent with the pattern observed across the North Shore from Baie-Comeau to Havre-Saint-Pierre — all drawing from Shield rivers and producing soft water.

With 41 mg/L of hardness, Sept-Îles homes are largely scale-free — occasional kettle descaling every three to four months is sufficient. Hot water tanks have an excellent operational lifespan. Ville de Sept-Îles publishes annual water quality reports following Ministère de l'Environnement standards; Sept-Îles' role as a major iron ore and aluminum port means the water system is subject to rigorous environmental monitoring, and residents are encouraged to consult the annual quality report for information on industrial-era copper and lead plumbing concerns in older downtown properties.