Well water hardness in Oklahoma
Across 24 counties of Oklahoma, the median well sampled by the USGS has 15.4 gpg of hardness. Counties range from 6.4 gpg (Delaware County) to 22.2 gpg (Alfalfa 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 | ||
|---|---|---|---|---|
| Alfalfa County | 22.2 | 380 | 12 | very hard |
| Canadian County | 20.4 | 350 | 20 | very hard |
| Johnston County | 20.3 | 348 | 21 | very hard |
| Custer County | 18.5 | 317 | 13 | very hard |
| Murray County | 18 | 309 | 39 | very hard |
| Woods County | 17.8 | 305 | 40 | very hard |
| Grady County | 16.7 | 286 | 28 | very hard |
| Kingfisher County | 16.6 | 285 | 26 | very hard |
| Major County | 16.1 | 275 | 36 | very hard |
| Blaine County | 15.8 | 270 | 21 | very hard |
| Craig County | 15.8 | 270 | 33 | very hard |
| Washita County | 15.7 | 269 | 10 | very hard |
| Logan County | 15.1 | 259 | 61 | very hard |
| Payne County | 14.4 | 247 | 15 | very hard |
| Caddo County | 14.1 | 242 | 88 | very hard |
| Texas County | 14 | 240 | 15 | very hard |
| Osage County | 13.8 | 236 | 140 | very hard |
| Oklahoma County | 12 | 205 | 251 | very hard |
| Creek County | 11.1 | 190 | 62 | very hard |
| Lincoln County | 11.1 | 190 | 97 | very hard |
| Ottawa County | 8.6 | 147 | 67 | hard |
| Pottawatomie County | 7.9 | 135 | 89 | hard |
| Cleveland County | 7.6 | 130 | 149 | hard |
| Delaware County | 6.4 | 110 | 32 | 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.
Oklahoma: tap water hardness by city → · Well water hardness by state and county →