Well water in Underhill, Vermont
In Underhill, 2% of 374 private wells tested had nitrate above the Vermont limit (10 mg/L), according to the Vermont Department of Health.
392 private wells tested in state summaries; 2 individual samples from 2 wells, 2003. Data refreshed September 3, 2026.
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 | |
|---|---|---|---|---|---|---|---|
| Nitrate | 374 | 2% | 0.25 | 2.6 | 18.7 | 10 mg/L | |
| Gross alpha Gross Alpha | 208 | 2% | 1.4 | 10.8 | 27.2 | 15 pCi/L | |
| Fluoride | 392 | 0% | 0.11 | 0.18 | 1.26 | 4 mg/L | |
| Arsenic | 325 | 0% | * | * | 4 | 10 ug/L | |
| Uranium | 317 | 0% | * | 3 | 11 | 20 ug/L | |
| Radon | 21 | 0% | 1,090 | 2,400 | 3,360 | 4,000 pCi/L |
* suppressed by the publisher because too few wells were tested.
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What this means
Among homeowners in Underhill who sent a sample to the state lab, the health-based limits most often exceeded were nitrate (2% of 374 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 Underhill
- Volatile organic compounds (VOCs)12 leaking underground storage tank sites on record locally.
- PFAS1 unlined landfill on record locally.
- Nitrate2% of 374 local wells tested were above the Vermont limit.
- Gross alpha2% of 208 local wells tested were above the Vermont limit.
- Coliform bacteriaRecommended for every private well, every year.
- ManganeseDetected in 100% of local samples.
Wells in Underhill
395 domestic wells in Underhill are on record with the state since 1996. 96% are drilled into bedrock, and the typical well is 350 feet deep (one in ten goes past 604 feet).
In a typical Underhill well, bedrock starts about 30 feet down, the median yield is 9 gallons per minute, 20% 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 Underhill
Vermont ANR records 12 leaking underground storage tank sites and 1 unlined landfill in Underhill, among 20 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.
- 12
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 1
- unlined landfillOlder unlined landfills are a leading source of PFAS, VOCs and metals in nearby wells.
- 7
- 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
- Manganese
- Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
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Common questions
How deep are wells in Underhill?
The typical domestic well in Underhill is 350 feet deep, based on 395 wells reported to the state since 1996. One in ten is deeper than 604 feet. 96% are drilled into bedrock.
Is there arsenic in well water in Underhill?
Arsenic was detected in 0% of 2 public well samples in Underhill, 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 Underhill?
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
- USGS Water Quality Portal: 14 samples in Underhill. 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 Underhill, up to 392 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: 400 well records in Underhill, 395 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: 20 regulated sites located in Underhill. 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.