Well Water Nerd

Well water in Knowlton township, New Jersey

In Knowlton township, 27% of 506 private wells tested between 2002 and 2024 had total coliform above the New Jersey limit (any detection), according to NJDEP.

507 private wells tested 2002 to 2024 in state summaries; 2 individual samples from 2 wells, 1991 to 1995. 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 coliform50627%
Manganese50721%50 ug/L
Iron50720%300 ug/L
Gross alpha1893%15 pCi/L
E. coli
Fecal coliform or
5062%
Arsenic3671%5 ug/L
PFOA791%14 ng/L
Nitrate5071%10 mg/L
Uranium1640%30 ug/L
PFNA790%13 ng/L
PFOS790%13 ng/L

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What this means

Among homeowners in Knowlton township who sent a sample to the state lab, the health-based limits most often exceeded were total coliform (27% of 506 wells), E. coli (2% of 506 wells), and arsenic (1% of 367 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 Knowlton township

  • Total coliform27% of 506 local wells tested were above the New Jersey limit (any detection).
  • Manganese21% of 507 local wells tested were above the New Jersey nuisance level.
  • Iron20% of 507 local wells tested were above the New Jersey nuisance level.
  • Gross alpha3% of 189 local wells tested were above the New Jersey limit.
  • E. coli2% of 506 local wells tested were above the New Jersey limit (any detection).
  • Arsenic1% of 367 local wells tested were above the New Jersey limit.
  • PFOA1% of 79 local wells tested were above the New Jersey limit.
  • Nitrate1% of 507 local wells tested were above the New Jersey limit.

Contamination sources on record in Knowlton township

NJDEP records 33 regulated sites in Knowlton township, among 33 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.

31
registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
2
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 Knowlton 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 Knowlton 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

Is there arsenic in well water in Knowlton township?

Arsenic was detected in 0% of 2 public well samples in Knowlton 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 often should I test a private well in Knowlton 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: 2 samples in Knowlton 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 Knowlton township, up to 507 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: 33 regulated sites located in Knowlton 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.