Uranium and manganese are widespread in Hancock County wells.
2 widespread, 1 likely overstated, 3 rare out of 6 health checks.
From 27 wells tested in Hancock County since 2002; your own well needs its own test. How to read this
*Arsenic: All of these tests come from the US Geological Survey between 2002 and 2007, so this likely overstates it.
Rare: under 5%Worth checking: 5 to 15%Widespread: 15%+
Lab results: Water Quality Portal (USGS and EPA)
Who drinks from a well here
7 in 10 people 37,979 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 Hancock County compares with Maine and the counties around it.
Each result puts Hancock County next to the 4 counties that border it, on the chart's 0 to 50% scale.
These 2 are widespread in Hancock County wells.
Uranium5 of 15 wells over
Too few tested to show: Penobscot, Waldo, Washington.
Manganese3 of 18 wells over
Too few tested to show: Penobscot, Waldo, Washington.
This one has turned up often here, mostly in older study samples.
Arsenic16 of 24 wells over
* Likely overstated, so we don't rank it.
Too few tested to show: Penobscot, Waldo.
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.
These 3 are rare in Hancock County.
Nitrate0 of 23 wells over
Too few tested to show: Penobscot, Waldo, Washington.
Lead0 of 15 wells over
Too few tested to show: Penobscot, Waldo, Washington.
Fluoride0 of 15 wells over
Too few tested to show: Penobscot, Waldo, Washington.
Every well needs a bacteria test every year.
No bacteria tests from Hancock County wells are in the public data. Test every year anyway.
Iron reached staining levels in 3 of 18 tested wells, and it isn't a health risk.
Iron stains3 of 18 wells had it
Too few tested to show: Penobscot, Waldo, Washington.
Most of the 27 wells tested in Hancock County were last tested before 2010.
An old result shows the water as it was then, so treat these 27 wells as a starting point and test your own.
Most Hancock 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 5 things to check in Hancock County.
- Bacteria
- Nitrate
- Arsenic
- Uranium
- 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 225 feet.
That comes from 6,657 household wells in Maine's drilling records. Most wells of every kind here are 159 to 320 feet deep. Wells as deep as Hancock 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 8 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 Hancock County.
Hancock 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 3 town water systems in Hancock County test for PFAS. 2 found some PFAS, all below the new limits. No well in Hancock 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 Hancock County
Is well water in Hancock County safe to drink?
16 of 24 wells tested in Hancock County had arsenic over the limit, about 2 in 3. 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 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. So test your own well for arsenic before you count on it.
Where can I get my well tested in Hancock 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, uranium and manganese, the tests that matter most in Hancock County.
How deep are wells in Hancock County?
Half the household wells here are shallower than 225 feet. Typical household wells here go deeper than in 8 of the 15 other Maine counties with enough drilling records.
How does Hancock County compare with the counties around it?
For arsenic, the share of tested wells over the limit: 2 of the 2 neighboring counties with data had a higher share than Hancock County, at 67%. Knox had the most, at 100%. Groundwater doesn't stop at county lines, so Knox's 100% is worth knowing about if you live near it.
How often should I test my well in Hancock County?
Hancock County has no public bacteria results for wells, so follow the CDC's advice: test for bacteria and nitrate every year, and right away after a flood, a repair, or any change in taste or smell.
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Where the Hancock County numbers come from
- People on wells: 37,979 in Hancock County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 185 well water samples from 27 wells in the Water Quality Portal, run by the USGS and EPA, 2002 to 2007.
- Well depths: 6,657 Maine drilling records for Hancock County, gathered in the US Groundwater Well Database (Lin and others, 2024).
- Neighboring counties: the 4 counties that share a border with Hancock 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 3 town water systems in Hancock County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Hancock 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.