PFOS in New Hampshire well water
In New Hampshire, 11% of 6,106 tested private well samples exceeded the EPA limit for PFOS (4 ng/L).
PFOS is a forever chemical with the same sources as PFOA. It is linked to immune suppression, thyroid disease, liver effects and cancer. Wells near airports, fire training areas, landfills and plating plants are most at risk.
By county, from individual samples
Public monitoring samples against the EPA limit (4 ng/L); counties with at least 30 samples.
| County | Samples | Detected | Above EPA limit | Median | Highest |
|---|---|---|---|---|---|
| Rockingham | 2,125 | 75% | 13% | 1.2 | 54.7 ng/L |
| Hillsborough | 3,795 | 74% | 10% | 0.97 | 71 ng/L |
| Strafford | 157 | 36% | 4% | 0 | 20 ng/L |
- Hudson, Hillsborough County28% of 46
- Greenland, Rockingham County20% of 150
- Hampton, Rockingham County15% of 39
- Exeter, Rockingham County14% of 65
- Londonderry, Rockingham County13% of 1,523
- Bedford, Hillsborough County11% of 3,053
- North Hampton, Rockingham County9% of 43
- Merrimack, Hillsborough County9% of 204
- Litchfield, Hillsborough County8% of 473
- Stratham, Rockingham County8% of 276
- Madbury, Strafford County5% of 88
- Dover, Strafford County3% of 63
Sources
- Individual samples from the USGS Water Quality Portal and state monitoring, summarized per geography. PFOS counts and shares are listed on each county and town page with their sources.