Only 1 health check had enough tested wells in Windham County, and it came back rare.
The only health check here came back rare.
From 10 wells tested in Windham County since 2000; your own well needs its own test. How to read this
Not charted, because fewer than 10 wells were tested: nitrate (2), uranium (2), radon (2), manganese (2), lead (2), fluoride (2).
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 52,619 people
Nobody else tests these wells. Only you do.
People on wells: EPA researchers' 2020 estimate
Radon risk (a gas from rock)
Possible here. A home air test is inexpensive.
Radon zones: EPA map
Here's how Windham County compares with Connecticut and the counties around it.
Each result puts Windham County next to the 5 counties that border it, on the chart's 0 to 50% scale.
The only health check in Windham County is rare.
Arsenic0 of 10 wells over
Too few tested to show: Kent, RI, Providence, RI, Tolland.
Too few Windham County wells were tested for these 6.
Nitrate2 wells tested
Uranium2 wells tested
Radon in water2 wells tested
Manganese2 wells tested
Lead2 wells tested
Fluoride2 wells tested
None of the 2 Windham County wells tested for bacteria had it, but every well needs a yearly test.
Coliform bacteria0 of 2 wells had it
E. coli0 of 2 wells had it
E. coli means human or animal waste is getting in, so if a test of your Windham County well finds it, boil drinking water until the well is fixed.
Iron reached staining levels in 1 of 10 tested wells, and it isn't a health risk.
Iron stains1 of 10 wells had it
Too few tested to show: Kent, RI, Providence, RI, Tolland.
Most of the 10 wells tested in Windham County were last tested before 2010.
An old result shows the water as it was then, so treat these 10 wells as a starting point and test your own.
Most Windham 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 3 things to check in Windham County.
- Bacteria
- Nitrate
- Arsenic
What Connecticut offers well owners
- Free testingWe didn't find a free program for all of Connecticut. Connecticut's private well page
- Certified labsConnecticut's list of certified labs
- Well recordsWe didn't find an online search.
- New wellsUnder Section 19a-37 of the Connecticut General Statutes, water testing is required for all new private wells, but testing at home sale is not required by law.
Here's what we know about radon and PFAS in Windham County.
Windham County is in the EPA's middle radon zone. An indoor air test is cheap and tells you whether to look at your water. Radon guide
Between 2023 and 2025 the EPA had 3 town water systems in Windham County test for PFAS. 2 of them had at least one test above 4 ng/L, the new EPA limit for PFOA and PFOS. The highest single result was 9.9 ng/L of PFOA. No well in Windham 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 Windham County
Is well water in Windham County safe to drink?
Most tested wells in Windham County came in under the limits. Of 1 health check with enough tests, arsenic came closest, at 0 of 10 wells over. Every well is different, so test yours for bacteria, nitrate and arsenic.
Where can I get my well tested in Windham County?
Use a lab Connecticut has certified for drinking water. Connecticut's list is linked above, in the box about testing. Ask for bacteria, nitrate and arsenic, the tests that matter most in Windham County.
How does Windham County compare with the counties around it?
For arsenic, the share of tested wells over the limit: 1 of the 2 neighboring counties with data had a higher share than Windham County, at 0%. Worcester, MA had the most, at 16%. Groundwater doesn't stop at county lines, so Worcester, MA's 16% is worth knowing about if you live near it.
How often should I test my well in Windham County?
None of the 2 wells tested for bacteria in Windham County had it, but the CDC still says to 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 Windham County numbers come from
- People on wells: 52,619 in Windham County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 45 well water samples from 10 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2017.
- Neighboring counties: the 5 counties that share a border with Windham County, from the Census Bureau's county adjacency file.
- PFAS: EPA tests of 3 town water systems in Windham County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Windham County is zone 2 on the EPA Map of Radon Zones.
- State programs and links: Department of Public Health, checked November 1, 2026.