Arsenic has turned up often in York County wells, mostly in older study samples.
1 likely overstated, 1 worth checking, 4 rare out of 6 health checks.
From 16 wells tested in York County since 2000; your own well needs its own test. How to read this
*Arsenic: All of these tests come from the US Geological Survey, mostly before 2013, so this likely overstates it.
Not charted, because fewer than 10 wells were tested: radon (5).
Rare: under 5%Worth checking: 5 to 15%Widespread: 15%+
Lab results: Water Quality Portal (USGS and EPA)
Who drinks from a well here
1 in 2 people 94,758 people
Nobody else tests these wells. Only you do.
People on wells: EPA researchers' 2020 estimate
How deep wells go here
Deep wells: fewer surface germs, more minerals from the rock.
Well depths: US Groundwater Well Database
Radon risk (a gas from rock)
Likely here. Test your home's air first.
Radon zones: EPA map
Here's how York County compares with Maine and the counties around it.
Each result puts York County next to the 5 counties that border it, on the chart's 0 to 50% scale.
This one has turned up often here, mostly in older study samples.
Arsenic10 of 16 wells over
* Likely overstated, so we don't rank it.
Too few tested to show: Carroll, NH, Oxford, Strafford, NH.
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.
This one is worth checking in York County.
Manganese1 of 16 wells over
Too few tested to show: Carroll, NH, Oxford, Strafford, NH.
These 4 are rare in York County.
Uranium0 of 13 wells over
Too few tested to show: Carroll, NH, Oxford, Strafford, NH.
Nitrate0 of 13 wells over
Too few tested to show: Carroll, NH, Oxford, Strafford, NH.
Lead0 of 13 wells over
Too few tested to show: Carroll, NH, Oxford, Strafford, NH.
Fluoride0 of 13 wells over
Too few tested to show: Carroll, NH, Oxford, Strafford, NH.
Too few York County wells were tested for this one.
Radon in water5 wells tested
Coliform bacteria turned up in 4 of 6 tested York County wells, so test for it every year.
Coliform bacteria4 of 6 wells had it
E. coli0 of 6 wells had it
E. coli means human or animal waste is getting in, so if a test of your York County well finds it, boil drinking water until the well is fixed.
Iron reached staining levels in 4 of 16 tested wells, and it isn't a health risk.
Iron stains4 of 16 wells had it
Too few tested to show: Carroll, NH, Oxford, Strafford, NH.
Most of the 16 wells tested in York County were last tested before 2010.
An old result shows the water as it was then, so treat these 16 wells as a starting point and test your own.
Most York County wells in these records were tested for research or because someone suspected a problem, which can push the shares above what a typical home well would show (how we read the numbers).
One mail-in lab test covers the 4 things to check in York County.
- Bacteria
- Nitrate
- Arsenic
- Manganese
What Maine offers well owners
- Free testingWe didn't find a free program for all of Maine. Maine's private well page
- Certified labsMaine's list of certified labs
- Well recordsMaine's well record search
Half the household wells here are shallower than 280 feet.
That comes from 9,897 household wells in Maine's drilling records. Most wells of every kind here are 180 to 400 feet deep. Wells as deep as York County's are usually better protected from fertilizer and bacteria at the surface, but they can pick up more of what's in the rock, like arsenic and uranium. Typical household wells here go deeper than in 13 of the 15 other Maine counties with enough drilling records.
Look up your own well's depth in Maine's well record search, or see how to find it.
Well depths: US Groundwater Well Database
Here's what we know about radon and PFAS in York County.
York County is in the EPA's highest radon zone. Radon from well water adds to the radon in your indoor air, so test your air first, and your water too if the air is high. Radon guide
Between 2023 and 2025 the EPA had 9 town water systems in York County test for PFAS. 1 of them had at least one test above 4 ng/L, the new EPA limit for PFOA and PFOS. The highest single result was 7.1 ng/L of PFOS. Only 1 well in York County has public PFAS results, so the town systems are the best clue to what's in the groundwater nearby. PFAS guide
Radon zones: EPA Map of Radon Zones. PFAS: EPA tests of town water systems, 2023 to 2025
Questions people ask about well water in York County
Is well water in York County safe to drink?
10 of 16 wells tested in York County had arsenic over the limit, about 6 in 10. Across Maine it's about 1 in 10. We don't rank this against other Maine counties, because most of these tests are old study samples. 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. So test your own well for arsenic before you count on it.
Where can I get my well tested in York County?
Use a lab Maine has certified for drinking water. Maine's list is linked above, in the box about testing. Ask for bacteria, nitrate, arsenic and manganese, the tests that matter most in York County.
How deep are wells in York County?
Half the household wells here are shallower than 280 feet. Typical household wells here go deeper than in 13 of the 15 other Maine counties with enough drilling records.
How does York County compare with the counties around it?
For arsenic, the share of tested wells over the limit: York County, at 62%, had a higher share than all 2 neighboring counties with data. Groundwater doesn't stop at county lines, so Cumberland's 41% is worth knowing about if you live near it.
How often should I test my well in York County?
In York County, 4 of 6 tested wells had coliform bacteria, so the CDC's advice matters here: test for bacteria and nitrate every year, and right away after a flood, a repair, or any change in taste or smell.
If you buy something through our links, we may earn a commission. We'd recommend the same thing either way, and we'll tell you when a free option exists. How we make money
Where the York County numbers come from
- People on wells: 94,758 in York County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 154 well water samples from 16 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2019.
- Well depths: 9,897 Maine drilling records for York County, gathered in the US Groundwater Well Database (Lin and others, 2024).
- Neighboring counties: the 5 counties that share a border with York County, from the Census Bureau's county adjacency file.
- Arsenic for comparison: Loiselle and others (2001), cited in USGS SIR 2010-5199.
- Results marked likely overstated: our own check of who tested the wells, when and where.
- PFAS: EPA tests of 9 town water systems in York County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: York County is zone 1 on the EPA Map of Radon Zones.
- State programs and links: Maine CDC (Department of Health and Human Services), Drinking Water Program, checked November 1, 2026.