South Milwaukee Water Hardness & Quality Report (2026)

South Milwaukee, Wisconsin, in Milwaukee County — a lakeshore Milwaukee County community on Lake Michigan south of Milwaukee, home of the historic Bucyrus International (now Caterpillar) mining equipment manufacturing plant, a classic Great Lakes industrial suburb — receives its municipal water from the South Milwaukee Water Utility, which draws from Lake Michigan through the South Milwaukee lakefront intake, or through the Milwaukee Metropolitan Sewerage District regional treated water supply.

The moderately hard 103 mg/L hardness and TDS of 241 mg/L reflect Lake Michigan's characteristic water chemistry at the Milwaukee lakefront. Lake Michigan draws from the Canadian Shield (Precambrian Laurentian granite and gneiss — soft) through the northern Michigan watershed but also from the Silurian Niagara Dolomite escarpment of the Door Peninsula (Wisconsin) and the Michigan Lower Peninsula dolomite platform. The Niagara Escarpment carbonate input and the Lower Peninsula dolomite tributary baseflow add moderate hardness to Lake Michigan's otherwise soft Canadian Shield baseline. South Milwaukee's groundwater note (the data lists groundwater) may indicate some local dolomite aquifer mixing, but the Milwaukee Water Works Lake Michigan supply is the dominant regional supply, producing consistent moderately hard finished water.

At 103 mg/L, South Milwaukee's water is moderately hard — scale builds in kettles and appliances over months, dishwashers benefit from rinse aid, and faucet aerators need periodic cleaning. Quarterly descaling of heating appliances is appropriate. The PFAS level of 3.2 ppt is favorable — excellent for a major industrial Lake Michigan lakefront municipality, reflecting the South Milwaukee lakeshore's relatively limited direct PFAS point sources and the Lake Michigan supply's dilution capacity for regional industrial discharge.