Well Water Nerd

Well water in Greenwich township, New Jersey

In Greenwich township, 22% of 245 private wells tested between 2002 and 2024 had total coliform above the New Jersey limit (any detection), according to NJDEP.

245 private wells tested 2002 to 2024 in state summaries. 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.

ContaminantWells testedAbove state levelMedian95th pctHighestState level
Total coliform24522%
Nitrate2459%10 mg/L
Iron2457%300 ug/L
Manganese2456%50 ug/L
Gross alpha775%15 pCi/L
E. coli
Fecal coliform or
244<1%
Arsenic1940%5 ug/L
Uranium680%30 ug/L
PFNA300%13 ng/L
PFOS300%13 ng/L
PFOA300%14 ng/L

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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 (22% of 245 wells), nitrate (9% of 245 wells), and E. coli (<1% of 244 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 Greenwich township

  • Total coliform22% of 245 local wells tested were above the New Jersey limit (any detection).
  • Nitrate9% of 245 local wells tested were above the New Jersey limit.
  • Iron7% of 245 local wells tested were above the New Jersey nuisance level.
  • Manganese6% of 245 local wells tested were above the New Jersey nuisance level.
  • Gross alpha5% of 77 local wells tested were above the New Jersey limit.
  • E. coli<1% of 244 local wells tested were above the New Jersey limit (any detection).

Contamination sources on record in Greenwich township

NJDEP records 19 regulated sites in Greenwich township, among 19 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.

16
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
Nitrate
Point-of-use reverse osmosis; Anion exchange; Distillation
Gross alpha
Point-of-use reverse osmosis; Water softener (cation exchange) for radium; Anion exchange for uranium
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

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.

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 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

  • NJDEP Private Well Testing Act summaries: summaries for 11 contaminants in Greenwich township, up to 245 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: 19 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.