Well water hardness in Maryland
Across 23 counties of Maryland, the median well sampled by the USGS has 3.7 gpg of hardness. Counties range from 0.3 gpg (Charles County) to 14.7 gpg (Washington 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 | ||
|---|---|---|---|---|
| Washington County | 14.7 | 252 | 53 | very hard |
| Calvert County | 8.4 | 143 | 41 | hard |
| Frederick County | 7.6 | 131 | 85 | hard |
| Baltimore City | 7.6 | 130 | 18 | hard |
| Montgomery County | 6.4 | 109 | 36 | moderately hard |
| Prince George's County | 5.3 | 90 | 19 | moderately hard |
| Baltimore County | 5.2 | 90 | 254 | moderately hard |
| Carroll County | 5 | 86 | 28 | moderately hard |
| Garrett County | 4.6 | 79 | 81 | moderately hard |
| Queen Anne's County | 4.3 | 73 | 114 | moderately hard |
| Worcester County | 3.9 | 66 | 121 | moderately hard |
| Harford County | 3.7 | 64 | 127 | moderately hard |
| Kent County | 3.1 | 53 | 146 | soft |
| Somerset County | 3.1 | 53 | 94 | soft |
| Talbot County | 3 | 51 | 21 | soft |
| Dorchester County | 2.6 | 45 | 71 | soft |
| Cecil County | 2.3 | 40 | 94 | soft |
| Caroline County | 2.2 | 38 | 90 | soft |
| Howard County | 2 | 35 | 104 | soft |
| Anne Arundel County | 1.8 | 31 | 172 | soft |
| Wicomico County | 1.5 | 26 | 92 | soft |
| St. Mary's County | 0.8 | 13 | 40 | soft |
| Charles County | 0.3 | 5 | 74 | soft |
Counties with fewer than 10 sampled wells, or a median outside 5–500 mg/L, are not shown until the figure is reviewed.
Maryland: tap water hardness by city → · Well water hardness by state and county →