Radon in Vermont well water
In Vermont, 8% of 2,351 private wells tested had radon above the Vermont advisory level (4,000 pCi/L), according to the Vermont Department of Health.
Radon is a radioactive gas released from bedrock into well water. It escapes into household air during showers and washing, where inhaling it raises lung cancer risk. EPA has no enforceable water MCL; New Hampshire recommends treatment above 2,000 pCi/L, and many states use 4,000 pCi/L.
By county, from homeowner tests
Share of private wells above the state guidance level (4,000 pCi/L) in tests homeowners sent to the state lab, to .
| County | Wells tested | Above state level | Highest | |
|---|---|---|---|---|
| Orleans | 214 | 20% | 33,500 pCi/L | |
| Orange | 51 | 18% | 20,900 pCi/L | |
| Windsor | 161 | 12% | 912,000 pCi/L | |
| Washington | 738 | 8% | 39,100 pCi/L | |
| Lamoille | 421 | 6% | 13,900 pCi/L | |
| Caledonia | 234 | 6% | 21,800 pCi/L | |
| Chittenden | 438 | 3% | 17,900 pCi/L | |
| Bennington | 31 | 0% | 2,130 pCi/L |
Towns with the highest share above the state level
- Westmore, Orleans County54% of 39 wells
- Randolph, Orange County23% of 31 wells
- Ludlow, Windsor County18% of 44 wells
- Barre, Washington County15% of 46 wells
- Hyde Park, Lamoille County14% of 35 wells
- Middlesex, Washington County11% of 35 wells
- Moretown, Washington County11% of 46 wells
- Berlin, Washington County10% of 31 wells
- Fayston, Washington County9% of 100 wells
- Waitsfield, Washington County9% of 82 wells
- Hinesburg, Chittenden County8% of 66 wells
- Burke, Caledonia County5% of 37 wells
- Warren, Washington County5% of 134 wells
- Calais, Washington County5% of 58 wells
- Stowe, Lamoille County5% of 284 wells
- Richmond, Chittenden County5% of 41 wells
- Morristown, Lamoille County4% of 76 wells
- East Montpelier, Washington County4% of 57 wells
- Norwich, Windsor County3% of 33 wells
- Hartford, Windsor County3% of 37 wells
- Waterbury, Washington County3% of 76 wells
- Shelburne, Chittenden County2% of 42 wells
- Derby, Orleans County2% of 43 wells
- Charlotte, Chittenden County1% of 89 wells
- Williston, Chittenden County0% of 52 wells
Sources
- Vermont Tracking private well summaries: Town summaries of private well tests reported to the Vermont Department of Health, published through Vermont Environmental Public Health Tracking. Shares are against the limit Vermont applies to each analyte: arsenic 10 ug/L, uranium 20 ug/L (stricter than EPA), fluoride 4 mg/L, nitrate 10 mg/L, gross alpha 15 pCi/L, radon 4,000 pCi/L advisory. Only towns with 20 or more results are published; statistics below the reporting limit show as *. Retrieved September 3, 2026.
- Individual samples from the USGS Water Quality Portal and state monitoring, summarized per geography. radon counts and shares are listed on each county and town page with their sources.