Superior Water Hardness & Quality Report (2026)

Superior, Wisconsin, the Douglas County seat — a major northwest Wisconsin Lake Superior port city (Superior is the Douglas County seat — one of the most important port cities on Lake Superior; Superior is the Wisconsin twin of Duluth, Minnesota (the Superior–Duluth metropolitan area spans the state line — the combined port of Duluth–Superior is one of the busiest freshwater ports in the world and the largest port on the Great Lakes by tonnage; the port handles enormous volumes of iron ore, coal, grain, and other bulk commodities for the Midwest industrial economy)); Superior is the home of the Richard I. Bong Veterans Historical Center (honoring Richard Bong — the American air ace who was the highest-scoring American fighter pilot in WWII with 40 aerial victories; Bong was from Poplar, Wisconsin, near Superior), home of the University of Wisconsin–Superior (a regional UW campus), a diverse Douglas County community with a significant Scandinavian-American, Native American (Lake Superior Ojibwe), and working-class port and industrial heritage population — draws its municipal water supply via the City of Superior Water Division. Water hardness in Superior measures 210 mg/L — classified as hard.

Superior's hard supply reflects the northwest Wisconsin Douglas County Lake Superior basin aquifer's calcareous character. The St. Louis River and Lake Superior watershed supplies water with dissolved carbonates from the Precambrian Duluth Complex (calcareous). Limited softening produces the hard 210 mg/L.

At 210 mg/L, Superior residents face regular hard water challenges. Monthly descaling and water softeners are recommended. City of Superior Water Division consistently delivers water meeting all Wisconsin DNR and EPA Safe Drinking Water Act requirements.