Manganese has turned up often in Chittenden County wells, mostly in older study samples.
1 likely overstated, 3 rare out of 4 health checks.
From 10 wells tested in Chittenden County since 2003; your own well needs its own test. How to read this
*Manganese: Almost all of these tests come from the US Geological Survey between 2003 and 2003 in one small part of the county, 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
1 in 4 people 43,177 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)
Less likely, but the EPA still says test your air.
Radon zones: EPA map
Here's how Chittenden County compares with Vermont and the counties around it.
Each result puts Chittenden County next to the 7 counties that border it, on the chart's 0 to 50% scale.
This one has turned up often here, mostly in older study samples.
Manganese2 of 10 wells over
* Likely overstated, so we don't rank it.
Too few tested to show: Addison, Franklin, Grand Isle, Lamoille, Washington.
Almost all of these tests come from the US Geological Survey between 2003 and 2003 in one small part of the county, so this likely overstates it.
These 3 are rare in Chittenden County.
Arsenic0 of 10 wells over
Too few tested to show: Addison, Franklin, Grand Isle, Lamoille, Washington.
Uranium0 of 10 wells over
Too few tested to show: Addison, Franklin, Grand Isle, Lamoille, Washington.
Lead0 of 10 wells over
Too few tested to show: Addison, Franklin, Grand Isle, Lamoille, Washington.
Every well needs a bacteria test every year.
No bacteria tests from Chittenden County wells are in the public data. Test every year anyway.
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: Addison, Franklin, Grand Isle, Lamoille, Washington.
All 10 wells tested in Chittenden County were tested in 2003.
An old result shows the water as it was then, so treat these 10 wells as a starting point and test your own.
Most Chittenden 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 Chittenden County.
- Bacteria
- Nitrate
- Manganese
- Arsenic
What Vermont offers well owners
- Free testingWe didn't find a free program for all of Vermont. Vermont's private well page
- Certified labsVermont's list of certified labs
- Well recordsVermont's well record search
- New wellsVermont law requires landowners to test the water from a new or deepened well or spring for 14 contaminants before using it; testing is not required at home sale, but sellers must give buyers an informational guide on testing.
Half the household wells here are shallower than 320 feet.
That comes from 10,102 household wells in Vermont's drilling records. Most wells of every kind here are 205 to 499 feet deep. Wells as deep as Chittenden 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. That's the deepest typical depth for household wells among the 14 Vermont counties with enough drilling records.
Look up your own well's depth in Vermont'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 Chittenden County.
Chittenden County is in the EPA's lowest radon zone, so radon from well water is unlikely to be a problem. Radon guide
Between 2023 and 2025 the EPA had 11 town water systems in Chittenden County test for PFAS. 1 found some PFAS, all below the new limits. No well in Chittenden 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 Chittenden County
Is well water in Chittenden County safe to drink?
2 of 10 wells tested in Chittenden County had manganese over the limit, about 2 in 10. Across Vermont it's about 2 in 10. We don't rank this against other Vermont counties, because most of these tests are old study samples. Almost all of these tests come from the US Geological Survey between 2003 and 2003 in one small part of the county, so this likely overstates it. So test your own well for manganese before you count on it.
Where can I get my well tested in Chittenden County?
Use a lab Vermont has certified for drinking water. Vermont's list is linked above, in the box about testing. Ask for bacteria, nitrate, manganese and arsenic, the tests that matter most in Chittenden County.
How deep are wells in Chittenden County?
Half the household wells here are shallower than 320 feet. That's the deepest typical depth for household wells among the 14 Vermont counties with enough drilling records.
How does Chittenden County compare with the counties around it?
For manganese, the share of tested wells over the limit: Chittenden County, at 20%, had a higher share than all 2 neighboring counties with data. Groundwater doesn't stop at county lines, so Clinton, NY's 5% is worth knowing about if you live near it.
How often should I test my well in Chittenden County?
Chittenden 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 Chittenden County numbers come from
- People on wells: 43,177 in Chittenden County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 50 well water samples from 10 wells in the Water Quality Portal, run by the USGS and EPA, 2003 to 2003.
- Well depths: 10,102 Vermont drilling records for Chittenden County, gathered in the US Groundwater Well Database (Lin and others, 2024).
- Neighboring counties: the 7 counties that share a border with Chittenden County, from the Census Bureau's county adjacency file.
- Results marked likely overstated: our own check of who tested the wells, when and where.
- PFAS: EPA tests of 11 town water systems in Chittenden County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Chittenden County is zone 3 on the EPA Map of Radon Zones.
- State programs and links: Department of Health, checked November 1, 2026.