Well water hardness in Montana
Across 38 counties of Montana, the median well sampled by the USGS has 12.3 gpg of hardness. Counties range from 4.7 gpg (Ravalli County) to 24.8 gpg (Prairie 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 | ||
|---|---|---|---|---|
| Prairie County | 24.8 | 425 | 10 | very hard |
| Phillips County | 23.9 | 410 | 21 | very hard |
| Sheridan County | 23.1 | 395 | 102 | very hard |
| Rosebud County | 21.6 | 370 | 52 | very hard |
| Blaine County | 20.5 | 351 | 80 | very hard |
| Roosevelt County | 19.7 | 337 | 96 | very hard |
| Richland County | 19.6 | 336 | 48 | very hard |
| Teton County | 18.3 | 314 | 30 | very hard |
| Liberty County | 17.1 | 293 | 18 | very hard |
| Fergus County | 16.9 | 290 | 62 | very hard |
| Granite County | 15.7 | 268 | 19 | very hard |
| Daniels County | 15.3 | 262 | 14 | very hard |
| Carbon County | 15.1 | 259 | 65 | very hard |
| Big Horn County | 14.9 | 255 | 129 | very hard |
| Yellowstone County | 14.6 | 250 | 59 | very hard |
| Musselshell County | 14.3 | 245 | 56 | very hard |
| Valley County | 13.8 | 237 | 90 | very hard |
| Broadwater County | 13.7 | 234 | 25 | very hard |
| Judith Basin County | 12.3 | 210 | 67 | very hard |
| Gallatin County | 12.3 | 210 | 150 | very hard |
| Lewis and Clark County | 11.7 | 201 | 124 | very hard |
| Flathead County | 11.1 | 190 | 25 | very hard |
| Glacier County | 10.8 | 185 | 22 | very hard |
| Madison County | 10.2 | 174 | 50 | hard |
| McCone County | 9.9 | 170 | 49 | hard |
| Powell County | 9.8 | 168 | 43 | hard |
| Beaverhead County | 9.6 | 164 | 104 | hard |
| Jefferson County | 9.5 | 162 | 126 | hard |
| Stillwater County | 9.3 | 160 | 15 | hard |
| Sweet Grass County | 9.3 | 160 | 40 | hard |
| Missoula County | 8.7 | 149 | 35 | hard |
| Lake County | 8.5 | 146 | 43 | hard |
| Dawson County | 8.2 | 140 | 25 | hard |
| Silver Bow County | 7.4 | 127 | 13 | hard |
| Sanders County | 6.7 | 115 | 30 | moderately hard |
| Powder River County | 5.2 | 90 | 32 | moderately hard |
| Lincoln County | 5 | 86 | 34 | moderately hard |
| Ravalli County | 4.7 | 80 | 113 | moderately hard |
Counties with fewer than 10 sampled wells, or a median outside 5–500 mg/L, are not shown until the figure is reviewed.
Montana: tap water hardness by city → · Well water hardness by state and county →