Private Well Water Testing in Maine
County-by-county USGS area-risk estimates for private wells across Maine — arsenic exceedance probability and private-well population — plus how to test your own well at a Maine-certified laboratory.
Maine private-well risk summary
Counties covered
16
Maine counties with modeled risk data.
People on private wells
area estimate513,260
estimated across covered Maine counties.
Average arsenic risk
area estimate18%
average modeled chance a well exceeds 10 µg/L arsenic across covered counties.
Maine counties
- York County19% arsenic exceedance (area estimate)61,987 people on private wells
- Penobscot County13% arsenic exceedance (area estimate)58,450 people on private wells
- Cumberland County20% arsenic exceedance (area estimate)54,095 people on private wells
- Kennebec County28% arsenic exceedance (area estimate)52,349 people on private wells
- Hancock County20% arsenic exceedance (area estimate)36,510 people on private wells
- Aroostook County13% arsenic exceedance (area estimate)35,896 people on private wells
- Oxford County5% arsenic exceedance (area estimate)33,053 people on private wells
- Androscoggin County45% arsenic exceedance (area estimate)31,097 people on private wells
- Somerset County12% arsenic exceedance (area estimate)25,980 people on private wells
- Waldo County11% arsenic exceedance (area estimate)25,685 people on private wells
- Lincoln County19% arsenic exceedance (area estimate)23,135 people on private wells
- Knox County9% arsenic exceedance (area estimate)18,809 people on private wells
- Washington County14% arsenic exceedance (area estimate)18,482 people on private wells
- Sagadahoc County34% arsenic exceedance (area estimate)15,499 people on private wells
- Franklin County10% arsenic exceedance (area estimate)12,970 people on private wells
- Piscataquis County11% arsenic exceedance (area estimate)9,263 people on private wells
Find a Maine-certified testing lab
Get your well tested at a Maine-certified laboratory. We list certification programs by state.
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Upload my well testThese figures are USGS area estimates: statistical groundwater models describing how likely elevated contaminant levels are across a county. They are not designed to predict the concentration in any single well. Only testing your own well reveals its water quality.
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