Well water hardness in Ohio
Across 35 counties of Ohio, the median well sampled by the USGS has 19.2 gpg of hardness. Counties range from 2.2 gpg (Vinton County) to 25.7 gpg (Wood 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 | ||
|---|---|---|---|---|
| Wood County | 25.7 | 440 | 58 | very hard |
| Franklin County | 25.4 | 435 | 105 | very hard |
| Union County | 25.2 | 432 | 16 | very hard |
| Shelby County | 24.2 | 414 | 33 | very hard |
| Miami County | 24.1 | 413 | 19 | very hard |
| Sandusky County | 23.9 | 410 | 34 | very hard |
| Darke County | 23.7 | 406 | 17 | very hard |
| Clark County | 22.8 | 391 | 23 | very hard |
| Champaign County | 22.4 | 384 | 18 | very hard |
| Greene County | 22.2 | 380 | 42 | very hard |
| Licking County | 21 | 359 | 17 | very hard |
| Montgomery County | 21 | 359 | 105 | very hard |
| Preble County | 21 | 359 | 32 | very hard |
| Jefferson County | 20.9 | 358 | 16 | very hard |
| Pike County | 20.9 | 358 | 46 | very hard |
| Hamilton County | 20.9 | 357 | 31 | very hard |
| Butler County | 19.3 | 330 | 37 | very hard |
| Stark County | 19.2 | 329 | 15 | very hard |
| Wayne County | 19.2 | 328 | 13 | very hard |
| Tuscarawas County | 19.1 | 327 | 32 | very hard |
| Morgan County | 17.5 | 300 | 16 | very hard |
| Washington County | 17.2 | 294 | 13 | very hard |
| Williams County | 17.1 | 293 | 58 | very hard |
| Portage County | 16.9 | 289 | 34 | very hard |
| Perry County | 15.8 | 270 | 18 | very hard |
| Lucas County | 15.6 | 267 | 38 | very hard |
| Harrison County | 15.4 | 263 | 10 | very hard |
| Athens County | 15.2 | 260 | 19 | very hard |
| Coshocton County | 14.4 | 246 | 18 | very hard |
| Muskingum County | 13.3 | 229 | 28 | very hard |
| Belmont County | 11.3 | 193 | 11 | very hard |
| Geauga County | 10.9 | 187 | 75 | very hard |
| Guernsey County | 10.8 | 185 | 16 | very hard |
| Hocking County | 5.5 | 95 | 15 | moderately hard |
| Vinton County | 2.2 | 37 | 24 | soft |
Counties with fewer than 10 sampled wells, or a median outside 5–500 mg/L, are not shown until the figure is reviewed.
Ohio: tap water hardness by city → · Well water hardness by state and county →