Wisconsin utilities with very hard water.
Above 180 mg/L (10.5 grains per gallon). 580 utilities serving 1.6 million people as they report it, largest first.
401 to 500 of 580, by people served
Source: Wisconsin Department of Natural Resources, Drinking Water Program, 940 utilities, results from Feb. 4, 2015 to Sept. 24, 2026, read Oct. 10, 2026. Each sampling point is taken at its median; a figure is typical where every point falls in one band.
Bands are the U.S. Geological Survey’s, at 17.1 mg/L to the grain. People served is what each utility reports; where one sells water to another, the same people can be counted twice. How hardness is measured here.
Where to go next
- Wisconsin hardnessEvery band in the state, with the largest utilities in each.Wisconsin water hardness
- Softeners comparedCertified softeners and what each costs over five years, salt included, at your water’s hardness.Softeners, salt included
- Hardness across the USEvery state with hardness results, and the hardest and softest large utilities.US water hardness