Well water in Stillwater township, New Jersey
In Stillwater township, 31% of 627 private wells tested between 2002 and 2024 had total coliform above the New Jersey limit (any detection), according to NJDEP.
627 private wells tested 2002 to 2024 in state summaries; 15 individual samples from 13 wells, 1993 to 2022. Data refreshed September 9, 2026.
What homeowner tests found
NJDEP Private Well Testing Act summaries: private wells tested and reported to the state, 2002 to 2024. Shares are against the level the state applies to each contaminant, named in the last column; several are stricter than EPA.
What individual samples found
Each row summarizes every public sample for that contaminant inside Stillwater township. 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 | Samples | Detected | Above limit | Median | Highest | Limit | |
|---|---|---|---|---|---|---|---|
| Radium (226 + 228) 2004 to 2022 | 15 | 100% | 0% | 0.205 | 2.7 | 5 pCi/L EPA limit | |
| Uranium 2004 to 2022 | 13 | 100% | 0% | 0.411 | 2.64 | 30 ug/L EPA limit | |
| Radon 2004 | 12 | 100% | no limit | 985 | 2,080 | 2,000 pCi/L health guideline |
Sampled fewer than 10 times, too few to summarize: PFOS (1), PFOA (1), Arsenic (4), Nitrate (1).
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What this means
Among homeowners in Stillwater township who sent a sample to the state lab, the health-based limits most often exceeded were total coliform (31% of 627 wells), E. coli (4% of 620 wells), and PFOS (3% of 108 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.
Manganese and iron exceed the state's advisory level in a sizable share of wells; these are mostly a taste, staining or diet issue rather than a toxicity one.
What to test for in Stillwater township
- Manganese36% of 627 local wells tested were above the New Jersey nuisance level.
- Total coliform31% of 627 local wells tested were above the New Jersey limit (any detection).
- Iron27% of 627 local wells tested were above the New Jersey nuisance level.
- E. coli4% of 620 local wells tested were above the New Jersey limit (any detection).
- Gross alpha4% of 221 local wells tested were above the New Jersey limit.
- PFOS3% of 108 local wells tested were above the New Jersey limit.
- Arsenic2% of 479 local wells tested were above the New Jersey limit.
- PFOA<1% of 108 local wells tested were above the New Jersey limit.
Contamination sources on record in Stillwater township
NJDEP records 20 regulated sites in Stillwater township, 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.
- 17
- registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
- 3
- other remediation projects
Treatment that fits the local profile
- Total coliform
- Inspect and repair the well cap and casing, then shock chlorinate and retest; UV disinfection whole-house; Chlorination system
- Manganese
- Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
- Iron
- Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
Get your Stillwater township water tested at home
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. Tell us what you need and we match you with a company that serves Stillwater township.
Common questions
Is there arsenic in well water in Stillwater township?
Arsenic was detected in 75% of 4 public well samples in Stillwater township, 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 high is radon in well water in Stillwater township?
The median radon level across 12 public samples in Stillwater township was 985 pCi/L, with a high of 2,080 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Stillwater township?
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: 47 samples in Stillwater township. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
- NJDEP Private Well Testing Act summaries: summaries for 11 contaminants in Stillwater township, up to 627 wells each. Share of private wells exceeding each standard in tests required at sale or lease under the New Jersey Private Well Testing Act, September 2002 to December 2024, published by NJDEP. Tests are untreated water at the time of sale or lease, so every well is counted once per transaction. Municipalities with fewer than ten wells are suppressed. Standards are New Jersey's: arsenic 5 ug/L, PFOA 14 ng/L, PFOS 13 ng/L, PFNA 13 ng/L, manganese and iron secondary standards. Uranium and PFAS were added to the required panel in 2021 and 2020, so their well counts are smaller. Retrieved September 9, 2026.
- NJDEP regulated sites: 20 regulated sites located in Stillwater township. Known Contaminated Sites, regulated underground storage tank facilities and solid waste landfills from the New Jersey Department of Environmental Protection (NJ-GeoWeb). Retrieved September 9, 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.