Your county health department
Maine doesn't run a statewide free testing program that we know of. Some county health departments test wells or sell kits, so call yours first.
Maine's private well pageArsenic in Maine well water, by county
Arsenic has turned up often in 8 of the 8 Maine counties with 10 or more tested wells, but those results likely overstate it, because of who tested the wells, when or where. A county's share tells you how likely a problem is nearby. Only a test of your own well tells you what's in it.
How Maine compares with the rest of the country
A random sample of about 1,000 household wells found about 1 in 10 Maine wells over the limit. The public lab data put it at 67% of tested wells, but those wells were picked by research and monitoring programs, not at random. Across all tested wells in the US it's about 1 in 9. Maine is about average, so the county you live in tells you more than the state does.
Why it matters: Drinking it for years raises the risk of skin, bladder and lung cancer.
Arsenic dissolves out of certain rocks and old sediments, so it can be high even where nobody has polluted anything.
Arsenic in tested wells, county by county
Share of each county's tested wells with at least one result over the EPA limit of 10 µg/L. Counties need 10 or more tested wells to be listed. Widespread means 15% or more, worth checking 5 to 15%, rare under 5%.
| County | Wells tested | Wells over the limit | Level |
|---|---|---|---|
| Knox County | 13 | Widespread | |
| Kennebec County | 58 | Widespread | |
| Washington County | 12 | Widespread | |
| Hancock County | 24 | Widespread | |
| York County | 16 | Widespread | |
| Androscoggin County | 10 | Widespread | |
| Somerset County | 11 | Widespread | |
| Cumberland County | 44 | Widespread |
* Likely overstated. These shares come from a narrow set of wells, so they probably run high for the county as a whole:
- Knox County: All of these tests come from the US Geological Survey between 2001 and 2007, so this likely overstates it. A random sample of about 1,000 household wells found about 1 in 10 Maine wells over the limit.
- Kennebec County: All of these tests come from the US Geological Survey between 2000 and 2011, so this likely overstates it. Household tests at Maine's state lab from 2005 to 2009 found about 3 in 10 Kennebec County wells over the limit.
- Washington County: All of these tests come from the US Geological Survey, mostly before 2013 in one small part of the county, so this likely overstates it. A random sample of about 1,000 household wells found about 1 in 10 Maine wells over the limit.
- Hancock County: All of these tests come from the US Geological Survey between 2002 and 2007, so this likely overstates it. A random sample of about 1,000 household wells found about 1 in 10 Maine wells over the limit.
- York County: All of these tests come from the US Geological Survey, mostly before 2013, so this likely overstates it. Household tests at Maine's state lab from 2005 to 2009 found about 1 in 4 York County wells over the limit.
- Androscoggin County: All of these tests come from the US Geological Survey, so this likely overstates it. A random sample of about 1,000 household wells found about 1 in 10 Maine wells over the limit.
- Somerset County: All of these tests come from the US Geological Survey, mostly before 2013 in one small part of the county, so this likely overstates it. A random sample of about 1,000 household wells found about 1 in 10 Maine wells over the limit.
- Cumberland County: All of these tests come from the US Geological Survey, mostly before 2013, so this likely overstates it. Household tests at Maine's state lab from 2005 to 2009 found about 2 in 10 Cumberland County wells over the limit.
6 more Maine counties have 1 to 9 tested wells for arsenic, too few to rate.
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Where to get your well tested for arsenic in Maine
A lab Maine certifies
Ask for arsenic by name. Results from a certified lab count for a home sale or a loan.
Labs certified by MaineA mail-in kit
Fill the bottles at your kitchen tap and mail them back. We mark the kits that include arsenic.
Compare kitsKeep reading about wells in Maine
- Well water testing in Maine: how to get tested and what turns up statewide
- Arsenic in well water: where it comes from, what it does and how to remove it
- Nitrate in Maine wells, by county
- Uranium in Maine wells, by county
- Manganese in Maine wells, by county
- Lead in Maine wells, by county
Questions people ask about arsenic in Maine
Is there arsenic in Maine well water?
Arsenic has turned up often in 8 of the 8 Maine counties with 10 or more tested wells, but those results likely overstate it, because of who tested the wells, when or where. A random sample of about 1,000 household wells found about 1 in 10 Maine wells over the limit. The public lab data put it at 67% of tested wells, but those wells were picked by research and monitoring programs, not at random. Across all tested wells in the US it's about 1 in 9. Maine is about average, so the county you live in tells you more than the state does.
Where can I get my well tested for arsenic in Maine?
Use a lab certified by Maine for drinking water, or a mail-in kit that includes arsenic from a certified lab. Some county health departments test wells too, so call yours first.
See Maine's list of certified labs, or compare mail-in kits.
Where these numbers come from
- Lab tests: Water Quality Portal (USGS and EPA), well samples since 2000. A well counts as over if any of its tests was over the EPA limit of 10 µg/L. Wells tested for studies and monitoring, not a random sample of homes.
- Likely overstated: our own check of who tested the wells, when and where. How we check.
- State programs and links: Maine CDC (Department of Health and Human Services), Drinking Water Program.