Well water hardness in New Hampshire
Across 10 counties of New Hampshire, the median well sampled by the USGS has 3.3 gpg of hardness. Counties range from 1.9 gpg (Carroll County) to 4.3 gpg (Coos 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 | ||
|---|---|---|---|---|
| Coos County | 4.3 | 74 | 158 | moderately hard |
| Grafton County | 4.1 | 70 | 220 | moderately hard |
| Belknap County | 3.7 | 64 | 153 | moderately hard |
| Rockingham County | 3.6 | 61 | 145 | moderately hard |
| Merrimack County | 3.3 | 57 | 358 | soft |
| Sullivan County | 3.2 | 55 | 37 | soft |
| Hillsborough County | 2.8 | 48 | 104 | soft |
| Strafford County | 2.7 | 46 | 83 | soft |
| Cheshire County | 2.7 | 46 | 36 | soft |
| Carroll County | 1.9 | 33 | 206 | soft |
Counties with fewer than 10 sampled wells, or a median outside 5–500 mg/L, are not shown until the figure is reviewed.