How hard is the water in Manitowoc County, WI?
19 grains per gallon
A softener will pay its way here.
The median hardness measured in Manitowoc County, WI is 326 mg/L as calcium carbonate, which is 19 gpg. That is very hard on the USGS scale. It comes from 195 samples at 26 sites between 1990 and 2025, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 13 and 19.9 gpg. The whole middle of that range gives the same answer, so a test of your own tap is unlikely to change it. Confidence in the county figure: high (how it is measured).
What to do next
At 19 gpg a softener pays its way here. Before you buy, check the quoted unit's grain capacity against the sizing table below, and ask whether it regenerates on demand, which uses less salt than a timer. Call your utility for its own report if you are on city water.
More on sizing a softener for your household.
From 8.4 to 30.4 gpg
The softest single sample on record in Manitowoc County was 144 mg/L and the hardest 520 mg/L, a 4-fold gap. The top quarter of sites read above 19.9 gpg and the bottom quarter below 13 gpg.
Wells 18.9 gpg, rivers and lakes 19.1 gpg
1 groundwater samples from 1 wells put the median at 324 mg/L. 194 surface samples from 25 sites put it at 327.5 mg/L. In Manitowoc County the rivers and lakes come out 0.2 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. The two sources are close, so the county figure should hold whichever one your tap is on.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 416 lb of salt a year (11 bags of 40 lb, about $75), and roughly 2,346 gallons of regeneration water. Installed, most units run $1,000 to $4,500; spread over 15 years with salt, that is about $175 a year.
Sizing at 19 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,140 | 24,000 | 139 lb |
| 2 | 2,280 | 24,000 | 277 lb |
| 4 | 4,560 | 32,000 | 555 lb |
| 6 | 6,840 | 48,000 | 832 lb |
Manitowoc County against the rest of Wisconsin
Among the 72 Wisconsin counties with data, Manitowoc County is number 16 of 72 counting from the hardest. Across the whole country it is harder than 82% of counties.
Softest in Wisconsin: Vilas County at 1.4 gpg. Hardest: Calumet County at 28.4 gpg. Closest to Manitowoc County: Kewaunee County (18.5), Rock County (20.4), Green County (20.5).