Well Water Nerd

Well water in Windsor, Maine

In Windsor, 8% of 147 private wells tested had arsenic above the Maine guideline (10 ug/L), according to Maine CDC.

197 private wells tested in state summaries; 25 individual samples from 25 wells, 2022 to 2026. Data refreshed September 3, 2026.

Maine DEP samples private wells near fields where sludge or septage was spread and near other known PFAS sources, and resamples detections. PFAS shares describe wells that were tested for a reason, not every well in the area. In that targeted sampling, 12% of 25 PFOA results in Windsor were above the EPA limit of 4 ng/L. In that targeted sampling, 4% of 25 PFOS results in Windsor were above the EPA limit of 4 ng/L.

What homeowner tests found

Maine Tracking Network 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.

ContaminantWells testedAbove state levelMedian95th pctHighestState level
Arsenic1478%10 ug/L
Manganese1465%300 ug/L
Uranium1414%30 ug/L
Fluoride1651%2 mg/L
Nitrate197<1%10 mg/L
Nitrite1970%1 mg/L

What individual samples found

Each row summarizes every public sample for that contaminant inside Windsor. 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.

ContaminantSamplesDetectedAbove limitMedianHighestLimit
PFOA
2022 to 2026
2544%12%07.94 ng/L
EPA limit
PFOS
2022 to 2026
2536%4%05.94 ng/L
EPA limit
PFNA
2022 to 2026
254%0%01.910 ng/L
EPA limit
PFHxS
2022 to 2026
2524%0%00.92110 ng/L
EPA limit

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What this means

Among homeowners in Windsor who sent a sample to the state lab, the health-based limits most often exceeded were arsenic (8% of 147 wells), uranium (4% of 141 wells), and fluoride (1% of 165 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 Windsor

  • Volatile organic compounds (VOCs)3 leaking underground storage tank sites on record locally.
  • PFAS1 unlined landfill on record locally.
  • PFOA12% of 25 local samples were above the limit.
  • Arsenic8% of 147 local wells tested were above the Maine guideline.
  • Manganese5% of 146 local wells tested were above the Maine guideline.
  • Uranium4% of 141 local wells tested were above the Maine guideline.
  • PFOS4% of 25 local samples were above the limit.
  • Fluoride1% of 165 local wells tested were above the Maine guideline.
  • Nitrate<1% of 197 local wells tested were above the Maine guideline.
  • Coliform bacteriaRecommended for every private well, every year.

Wells in Windsor

155 domestic wells in Windsor are on record with the state since 1970. 99% are drilled into bedrock, and the typical well is 223 feet deep (one in ten goes past 360 feet).

In a typical Windsor well, bedrock starts about 18 feet down, the median yield is 8 gallons per minute, 12% 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.

13
1970s
14
1980s
24
1990s
43
2000s
19
2010s
32
2020s

Contamination sources on record in Windsor

Maine DEP records 3 leaking underground storage tank sites and 1 unlined landfill in Windsor, 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
unlined landfillOlder unlined landfills are a leading source of PFAS, VOCs and metals in nearby wells.
2
other remediation projects

Treatment that fits the local profile

Arsenic
Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
PFOA
Granular activated carbon whole-house; Point-of-use reverse osmosis; Anion exchange
PFOS
Granular activated carbon whole-house; Point-of-use reverse osmosis; Anion exchange

Book a free water test in Windsor

A licensed local water treatment company tests your tap water in your home, walks you through the numbers, and quotes treatment only if something needs fixing. Free, about 30 minutes, no obligation.

What are you worried about?

The test is free and there is no obligation. Your details go only to the company named above, and we log the time and address of this request.

Common questions

How deep are wells in Windsor?

The typical domestic well in Windsor is 223 feet deep, based on 155 wells reported to the state since 1970. One in ten is deeper than 360 feet. 99% are drilled into bedrock.

How often should I test a private well in Windsor?

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

  • Maine DEP PFAS investigation: 100 samples in Windsor. PFAS results for private wells sampled by the Maine Department of Environmental Protection. Retrieved September 3, 2026.
  • Maine Tracking Network private well summaries: summaries for 6 contaminants in Windsor, up to 197 wells each. Town summaries of private well tests run by the Maine Health and Environmental Testing Laboratory, published by Maine CDC through the Maine Tracking Network. Shares are against Maine's guideline for each analyte (arsenic 10 ug/L, uranium 30 ug/L, fluoride 2 mg/L, manganese 0.3 mg/L, nitrate 10 mg/L, nitrite 1 mg/L). Towns with too few tests are suppressed (NR). Only the share above the guideline and wells tested are published; no medians. Retrieved September 3, 2026.
  • Maine Geological Survey well database: 159 well records in Windsor, 155 domestic. Well construction records reported to the Maine Geological Survey by licensed well drillers. Only aggregates are shown; owner names and addresses are never stored. Retrieved September 3, 2026.
  • Maine DEP regulated sites: 6 regulated sites located in Windsor. Remediation sites, leaking underground storage tanks and closed municipal landfills from the Maine Department of Environmental Protection. 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.