Well water in Cornwall, Vermont
In Cornwall, 5% of 123 private wells tested had uranium above the Vermont limit (20 ug/L), according to the Vermont Department of Health.
145 private wells tested in state summaries. Data refreshed .
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.
| Contaminant | Wells tested | Above state level | Median | 95th pct | Highest | State level | |
|---|---|---|---|---|---|---|---|
| Gross alpha Gross Alpha | 80 | 10% | 3.3 | 20.2 | 51.4 | 15 pCi/L | |
| Uranium | 123 | 5% | 2 | 28 | 64 | 20 ug/L | |
| Arsenic | 145 | 5% | * | 8 | 19 | 10 ug/L | |
| Nitrate | 137 | 0% | 0.25 | 3.22 | 8.6 | 10 mg/L | |
| Fluoride | 129 | 0% | 0.15 | 0.26 | 0.48 | 4 mg/L |
* suppressed by the publisher because too few wells were tested.
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What this means
Among homeowners in Cornwall who sent a sample to the state lab, the health-based limits most often exceeded were uranium (5% of 123 wells) and arsenic (5% of 145 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.
What to test for in Cornwall
- Volatile organic compounds (VOCs)3 leaking underground storage tank sites on record locally.
- Metals panel1 hazardous waste site on record locally.
- Gross alpha10% of 80 local wells tested were above the Vermont limit.
- Uranium5% of 123 local wells tested were above the Vermont limit.
- Arsenic5% of 145 local wells tested were above the Vermont limit.
- Coliform bacteriaRecommended for every private well, every year.
- NitrateRecommended for every private well, especially near farms or septic systems.
Wells in Cornwall
188 domestic wells in Cornwall are on record with the state since 1996. 99% are drilled into bedrock, and the typical well is 450 feet deep (one in ten goes past 701 feet).
In a typical Cornwall well, bedrock starts about 30 feet down, the median yield is 10 gallons per minute, 13% 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.
Contamination sources on record in Cornwall
Vermont ANR records 3 leaking underground storage tank sites, 1 hazardous waste site, and 1 reported spill or release in Cornwall, among 6 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.
- 3
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 1
- hazardous waste siteSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 1
- reported spill or releaseMost spills are fuel; a few are solvents or chemicals that reach the water table.
- 1
- registered underground storage tank siteRegistered 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
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Common questions
How deep are wells in Cornwall?
The typical domestic well in Cornwall is 450 feet deep, based on 188 wells reported to the state since 1996. One in ten is deeper than 701 feet. 99% are drilled into bedrock.
How often should I test a private well in Cornwall?
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.
Sources
- Vermont Tracking private well summaries: summaries for 5 contaminants in Cornwall, up to 145 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.
- Vermont ANR well completion reports: 195 well records in Cornwall, 188 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: 6 regulated sites located in Cornwall. 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.