Well water in Chittenden County, Vermont
In Chittenden County, 4% of 4,475 private wells tested had arsenic above the Vermont limit (10 ug/L), according to the Vermont Department of Health.
5,062 private wells tested in state summaries; 76 test results across 10 contaminants from at least 11 wells, 1980 to 2003; sodium has the most at 11. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
An estimated 30,713 people in Chittenden County get their drinking water from a private well, per USGS 2015 county water use. That is about 19% of residents.
Separately, the USGS national arsenic model estimates that 2% of the 30,713 people on private wells in Chittenden County draw water above 10 ug/L (the model's range is 1% to 2%), from geology and well depth rather than local tests.
What homeowner tests found
Vermont Tracking private well summaries: private wells tested and reported to the state. Shares are against the level the state applies to each contaminant, named in the last column; several are stricter than EPA. County and state figures combine the town summaries, weighted by wells tested; medians are not combined.
What individual samples found
Each row summarizes every public sample for that contaminant inside Chittenden County. Above limit means above the EPA maximum contaminant level; where EPA has no enforceable limit, the row shows a health guideline or nuisance level instead.
| Contaminant | Above limit | Samples | Detected | Median | Highest | Limit |
|---|---|---|---|---|---|---|
| Arsenic 2003 | 10 | 40% | 0 | 2.8 | 10 ug/L EPA limit | |
| Uranium 2003 | 10 | 80% | 0.1 | 0.6 | 30 ug/L EPA limit | |
| Lead 2003 | 10 | 0% | 0 | 0 | 15 ug/L EPA limit | |
| Copper 2003 | 10 | 60% | 0 | 0 | 1.3 mg/L EPA limit | |
| Sodium 1980 to 2003 | no limit | 11 | 73% | 1.9 | 47 | 20 mg/L health guideline |
| Manganese 1980 to 2003 | no limit | 11 | 100% | 90 | 1,000 | 300 ug/L health guideline |
| Iron 1980 to 2003 | no limit | 11 | 45% | 0 | 27,000 | 300 ug/L nuisance level |
Sampled fewer than 10 times, too few to summarize: Nitrate (1), Fluoride (1), Chloride (1).
Closer than the county
See the sampled wells near your address
The same records, drawn around one point: which wells within a few miles were sampled and what they found, how deep the wells next to you were drilled, and any leaking tank or cleanup site within a mile.
Check my addressWhat this means
Among homeowners in Chittenden County who sent a sample to the state lab, the health-based limits most often exceeded were arsenic (4% of 4,475 wells), uranium (2% of 4,228 wells), and nitrate (<1% of 4,814 wells). These are ordinary wells tested by their owners, so the shares are the best available picture of a typical well here, with one caveat: people test more often when they suspect a problem.
Radon was above the Vermont advisory level of 4,000 pCi/L in 3% of 438 wells. Radon in water matters because it moves into indoor air during showers and laundry.
What to test for in Chittenden County
- 1Arsenic4% of 4,475 local wells tested were above the Vermont limit.
- 2Uranium2% of 4,228 local wells tested were above the Vermont limit.
- 3Nitrate<1% of 4,814 local wells tested were above the Vermont limit.
- 4Fluoride<1% of 5,062 local wells tested were above the Vermont limit.
- 5Coliform bacteriaRecommended for every private well, every year.
- 6Gross alpha9% of 2,624 local wells tested were above the Vermont limit.
- 7Radon3% of 438 local wells tested were above the Vermont advisory level.
- 8ManganeseDetected in 100% of local samples.
- 9Volatile organic compounds (VOCs)610 leaking underground storage tank sites on record locally.
- 10PFAS11 unlined landfills on record locally.
- 11Metals panel239 hazardous waste sites on record locally.
Test your Chittenden County well for arsenic, uranium and nitrate
Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.
Order the Tap Score well water test kit, from $209Already tested? Upload the report
Just want bacteria checked first? Tap Score coliform and E. coli test, $99. Coliform and E. coli are the tests every well needs every year.
Want a quick look before paying for a lab? Home well water test strips on Amazon check hardness, iron, pH and nitrate in minutes. They are a screen, not a result: arsenic, bacteria, uranium and PFAS need a certified lab.
Affiliate links: the merchant pays us a commission and the price is the same for you. It does not change what the data above says. As an Amazon Associate we earn from qualifying purchases.
Where to get a well tested in Vermont: certified labs, state programs and prices.
Already have results back? Get your lab report read against the Chittenden County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
Wells in Chittenden County
4,721 domestic wells in Chittenden County are on record with the state since 1971. 96% are drilled into bedrock, and the typical well is 400 feet deep (one in ten goes past 675 feet).
In a typical Chittenden County well, bedrock starts about 27 feet down, the median yield is 6 gallons per minute, 29% of wells yield under 3 gallons per minute and usually need a storage tank.
Bedrock wells are where arsenic, uranium and radon come from: the water sits in fractures in granite and metamorphic rock and picks up whatever the rock carries. That is why testing for those three matters more here than in a dug or gravel well.
The rock under Chittenden County
Not a principal aquifer
The USGS map places this area outside any principal aquifer, which usually means wells here draw from fractured bedrock or thin local deposits rather than a large regional aquifer. Bedrock wells of that kind are where arsenic, radon and uranium turn up, and yields vary from well to well.
Classification from the USGS Principal Aquifers of the United States (national map, 2003 edition, GIS release 2015), read at the county centroid. A single well can sit in a different unit, especially near a boundary.
Official help in Vermont
Two places to start that are not selling anything: the state program that answers private well questions, and its list of labs certified to run drinking water tests. A certified lab is the difference between a result you can act on and a number.
- Drinking Water, Vermont Department of Health
- Certification Programs for Other Labs, Vermont Department of Health
Contamination sources on record in Chittenden County
Vermont ANR records 610 leaking underground storage tank sites, 11 unlined landfills, 239 hazardous waste sites, and 19 reported spills and releases in Chittenden County, among 1,264 regulated sites in total. Groundwater does not follow property lines, so a well within a few hundred feet of one of these is worth testing for what that site could release.
- 610
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 11
- unlined landfillsOlder unlined landfills are a leading source of PFAS, VOCs and metals in nearby wells.
- 239
- hazardous waste sitesSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 19
- reported spills and releasesMost spills are fuel; a few are solvents or chemicals that reach the water table.
- 385
- registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
Treatment that fits the local profile
Gross alpha
Point-of-use reverse osmosis; Water softener (cation exchange) for radium; Anion exchange for uranium
Manganese
Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
Systems we would look at first
Some links below are affiliate links. If you buy through one, the merchant pays us a commission at no extra cost to you. It does not change which products we list or what the data says.
For gross alpha
Under-sink reverse osmosis system
under-sink or countertop, about $300
Look for NSF/ANSI 58 certification listing the contaminant you need removed.
For manganese
Iron and manganese oxidizing filter
whole-house, at the point of entry, about $1,800
Air-injection or greensand media; fixes staining at the source.
Free, no obligation
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Common questions
How deep are wells in Chittenden County?
The typical domestic well in Chittenden County is 400 feet deep, based on 4,721 wells reported to the state since 1971. One in ten is deeper than 675 feet. 96% are drilled into bedrock.
Is there arsenic in well water in Chittenden County?
Arsenic was detected in 40% of 10 public well samples in Chittenden County, and 0% were above the EPA limit of 10 ug/L. Arsenic has no taste or smell; a lab test is the only way to know your level.
How often should I test a private well in Chittenden County?
Test for bacteria and nitrate every year. Test once for arsenic, uranium, radon, fluoride, manganese and PFAS, then again every three to five years or after any change in taste, color, or plumbing.
Towns in Chittenden County
- Bolton3% nitrate
- Burlington0% arsenic
- Charlotte2% arsenic
- Colchester1% uranium
- Essex7% arsenic
- Hinesburg9% arsenic
- Huntington2% arsenic
- Jericho<1% arsenic
- Milton3% arsenic
- Richmond3% arsenic
- Shelburne1% uranium
- South Burlington0% arsenic
- St. George10% uranium
- Underhill2% nitrate
- Westford12% arsenic
- Williston13% arsenic
3 towns have fewer than 30 public samples and are included in the Chittenden County totals above rather than shown separately: Buels gore, Essex Junction, Winooski.
Counties near Chittenden County
Closest first. Groundwater does not stop at a line on a map, so the next county over is a fair second opinion.
Want the numbers themselves? Download the Vermont dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 76 samples in Chittenden County. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
- Vermont Tracking private well summaries: summaries for 6 contaminants in Chittenden County, up to 5,062 wells each. Town summaries of private well tests reported to the Vermont Department of Health, published through Vermont Environmental Public Health Tracking. Shares are against the limit Vermont applies to each analyte: arsenic 10 ug/L, uranium 20 ug/L (stricter than EPA), fluoride 4 mg/L, nitrate 10 mg/L, gross alpha 15 pCi/L, radon 4,000 pCi/L advisory. Only towns with 20 or more results are published; statistics below the reporting limit show as *. Retrieved September 3, 2026.
- USGS national arsenic model (Ayotte 2017): estimated share of 30,713 people on private wells in Chittenden County above 10 ug/L of arsenic, from geology, well depth and land use. County estimates of domestic well users with arsenic above 10 ug/L from the USGS national logistic regression model (Ayotte, Medalie and Qi, 2017), with private well population from the USGS 2015 county water-use compilation (Dieter and others, 2018). Retrieved September 15, 2026.
- Vermont ANR well completion reports: 4,989 well records in Chittenden County, 4,721 domestic. Well completion reports filed with the Vermont Agency of Natural Resources since 1966. Only aggregates are shown; owner names and addresses are never stored. Retrieved September 3, 2026.
- Vermont ANR regulated sites: 1,264 regulated sites located in Chittenden County. Hazardous waste sites, landfills and underground storage tanks from the Vermont Agency of Natural Resources. Retrieved September 3, 2026.
Non-detects count as samples and are treated as zero when computing medians. Exactly at the limit counts as not above it. A sample belongs to the town containing the well's reported coordinates.