Well water in Greenwich township, New Jersey
In Greenwich township, 7% of 68 tested well samples exceeded the EPA limit for arsenic (10 ug/L), based on public data from USGS Water Quality Portal.
12 private wells tested 2002 to 2024 in state summaries; 68 individual samples from 30 wells, 1972 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.
| Contaminant | Wells tested | Above state level | Median | 95th pct | Highest | State level | |
|---|---|---|---|---|---|---|---|
| Iron | 12 | 67% | 300 ug/L | ||||
| Manganese | 12 | 67% | 50 ug/L | ||||
| Total coliform | 12 | 17% | |||||
| E. coli Fecal coliform or | 12 | 0% | |||||
| Nitrate | 12 | 0% | 10 mg/L | ||||
| Gross alpha | 11 | 0% | 15 pCi/L |
What individual samples found
Each row summarizes every public sample for that contaminant inside Greenwich 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 | |
|---|---|---|---|---|---|---|---|
| Arsenic 1975 to 2022 | 68 | 49% | 7% | 0 | 20 | 10 ug/L EPA limit |
Sampled fewer than 10 times, too few to summarize: Lead (2), Radium (226 + 228) (5), Uranium (3), Copper (2), Nitrate (1), Fluoride (1), Radon (6), Iron (1), Chloride (1), Sodium (1), Manganese (1).
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What this means
Among homeowners in Greenwich township who sent a sample to the state lab, the health-based limits most often exceeded were total coliform (17% of 12 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.
Iron and manganese 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 Greenwich township
- Volatile organic compounds (VOCs)1 hazardous waste site on record locally.
- Metals panel1 hazardous waste site on record locally.
- Iron67% of 12 local wells tested were above the New Jersey nuisance level.
- Manganese67% of 12 local wells tested were above the New Jersey nuisance level.
- Total coliform17% of 12 local wells tested were above the New Jersey limit (any detection).
- Arsenic7% of 68 local samples were above the limit.
- Coliform bacteriaRecommended for every private well, every year.
- RadonMedian local reading is 111 pCi/L.
- LeadAbove the limit in 1 of 2 local samples; too few to quote a rate.
- Radium (226 + 228)Above the limit in 1 of 5 local samples; too few to quote a rate.
Contamination sources on record in Greenwich township
NJDEP records 1 hazardous waste site in Greenwich township, among 42 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.
- 1
- hazardous waste siteSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 25
- registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
- 3
- lined landfills and transfer facilities
- 13
- 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
- Iron
- Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
- Manganese
- Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
- Arsenic
- Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
- Fluoride
- Point-of-use reverse osmosis; Activated alumina; Distillation
- Chloride
- Point-of-use reverse osmosis; Distillation
Get your Greenwich 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 Greenwich township.
Common questions
Is there arsenic in well water in Greenwich township?
Arsenic was detected in 49% of 68 public well samples in Greenwich township, and 7% 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 Greenwich township?
The median radon level across 6 public samples in Greenwich township was 111 pCi/L, with a high of 140 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Greenwich 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: 92 samples in Greenwich 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 6 contaminants in Greenwich township, up to 12 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: 42 regulated sites located in Greenwich 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.