West Allis Water Hardness & Quality Report (2026)

West Allis, Wisconsin, in Milwaukee County immediately west of Milwaukee — an historically significant industrial city, former home of Allis-Chalmers Manufacturing (one of the largest heavy machinery manufacturers in the world), now a densely built inner suburb — draws its municipal water supply from Lake Michigan via the Milwaukee Water Works, distributed through the West Allis Water Distribution System (City of West Allis Utilities). Water hardness in West Allis measures 260 mg/L — classified as very hard, one of the harder Lake Michigan-derived supplies in the Milwaukee metro area.

West Allis's very hard supply reflects the Milwaukee County industrial corridor distribution infrastructure. Lake Michigan water at the Milwaukee Water Works intake is moderately hard (approximately 120–140 mg/L from the lake source alone) — the Great Lakes Basin carbonate geology (Silurian Niagaran Dolomite, Ordovician Black River and Galena limestones of the Great Lakes watershed) contributes moderate calcareous content. However, the West Allis distribution system — built to serve the enormous Allis-Chalmers industrial complex (a manufacturing campus of over 150 acres at peak operation) with extensive industrial-age water infrastructure — has accumulated significant additional mineral content in its aged cast-iron and ductile-iron mains, producing the 260 mg/L very hard supply at West Allis.

At 260 mg/L, West Allis residents face significant hard water challenges. Scale deposits form rapidly on all fixtures and tile — monthly descaling with citric acid solution is essential maintenance. City of West Allis Utilities consistently delivers water meeting all Wisconsin DNR and EPA Safe Drinking Water Act requirements.