Well water hardness in Minnesota
Across 41 counties of Minnesota, the median well sampled by the USGS has 15.9 gpg of hardness. Counties range from 2.1 gpg (Pine County) to 27.6 gpg (Blue Earth County).
Millions of American households drink water from their own well. No utility tests that water and no water quality report covers it. These pages summarise the hardness the U.S. Geological Survey measured in wells county by county, so you know what to expect before you test your own well.
Counties, hardest first
| gpg | mg/L | wells | ||
|---|---|---|---|---|
| Blue Earth County | 27.6 | 473 | 15 | very hard |
| Cottonwood County | 23.2 | 398 | 24 | very hard |
| Hennepin County | 22.4 | 383 | 195 | very hard |
| Redwood County | 22.3 | 382 | 23 | very hard |
| Scott County | 20.4 | 350 | 11 | very hard |
| Rock County | 20.1 | 345 | 16 | very hard |
| Swift County | 20 | 343 | 14 | very hard |
| Kandiyohi County | 19 | 325 | 10 | very hard |
| Mahnomen County | 18.5 | 318 | 10 | very hard |
| Polk County | 18.3 | 314 | 73 | very hard |
| Stearns County | 18.1 | 310 | 53 | very hard |
| Olmsted County | 18 | 308 | 62 | very hard |
| Clearwater County | 17.6 | 302 | 18 | very hard |
| Otter Tail County | 17.6 | 301 | 61 | very hard |
| Becker County | 17.3 | 296 | 18 | very hard |
| Pope County | 17 | 291 | 64 | very hard |
| Fillmore County | 16.9 | 290 | 17 | very hard |
| Wadena County | 16.9 | 290 | 19 | very hard |
| Anoka County | 16.6 | 284 | 91 | very hard |
| Dakota County | 16.3 | 280 | 118 | very hard |
| Red Lake County | 15.9 | 273 | 13 | very hard |
| Beltrami County | 15.6 | 268 | 66 | very hard |
| Douglas County | 15.5 | 265 | 10 | very hard |
| Isanti County | 15.4 | 263 | 16 | very hard |
| Sherburne County | 15.1 | 258 | 76 | very hard |
| Mower County | 14.6 | 251 | 18 | very hard |
| Aitkin County | 14.4 | 247 | 11 | very hard |
| Marshall County | 14.4 | 247 | 17 | very hard |
| Goodhue County | 14 | 240 | 49 | very hard |
| Ramsey County | 14 | 239 | 50 | very hard |
| Mille Lacs County | 13.6 | 233 | 22 | very hard |
| Washington County | 12.4 | 212 | 37 | very hard |
| Hubbard County | 12.1 | 208 | 34 | very hard |
| Cass County | 10.9 | 187 | 29 | very hard |
| Itasca County | 10.5 | 180 | 18 | very hard |
| St. Louis County | 9.2 | 158 | 23 | hard |
| Crow Wing County | 8 | 137 | 20 | hard |
| Chisago County | 7.7 | 132 | 12 | hard |
| Carlton County | 6.7 | 116 | 34 | moderately hard |
| Cook County | 3.6 | 61 | 14 | moderately hard |
| Pine County | 2.1 | 36 | 14 | soft |
Counties with fewer than 10 sampled wells, or a median outside 5–500 mg/L, are not shown until the figure is reviewed.
Minnesota: tap water hardness by city → · Well water hardness by state and county →