Well water in Hopewell township, New Jersey
In Hopewell township, 16% of 772 private wells tested between 2002 and 2024 had nitrate above the New Jersey limit (10 mg/L), according to NJDEP.
772 private wells tested 2002 to 2024 in state summaries; 20 individual samples from 11 wells, 1986 to 2018. 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 | |
|---|---|---|---|---|---|---|---|
| Gross alpha | 762 | 59% | 15 pCi/L | ||||
| Iron | 772 | 24% | 300 ug/L | ||||
| Nitrate | 772 | 16% | 10 mg/L | ||||
| Total coliform | 770 | 7% | |||||
| Manganese | 772 | 5% | 50 ug/L | ||||
| PFOA | 141 | 4% | 14 ng/L | ||||
| PFOS | 141 | 1% | 13 ng/L | ||||
| E. coli Fecal coliform or | 770 | <1% | |||||
| Arsenic | 285 | 0% | 5 ug/L | ||||
| PFNA | 141 | 0% | 13 ng/L |
What individual samples found
Each row summarizes every public sample for that contaminant inside Hopewell 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) 1988 to 2018 | 14 | 86% | 7% | 2.85 | 6 | 5 pCi/L EPA limit | |
| Arsenic 1986 to 2018 | 20 | 15% | 0% | 0 | 0.3 | 10 ug/L EPA limit |
Sampled fewer than 10 times, too few to summarize: Uranium (8), Radon (5), Sodium (1).
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What this means
Among homeowners in Hopewell township who sent a sample to the state lab, the health-based limits most often exceeded were nitrate (16% of 772 wells), total coliform (7% of 770 wells), and PFOA (4% of 141 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 exceeds the state's advisory level in a sizable share of wells; this is mostly a taste, staining or diet issue rather than a toxicity one.
What to test for in Hopewell township
- Gross alpha59% of 762 local wells tested were above the New Jersey limit.
- Iron24% of 772 local wells tested were above the New Jersey nuisance level.
- Nitrate16% of 772 local wells tested were above the New Jersey limit.
- Total coliform7% of 770 local wells tested were above the New Jersey limit (any detection).
- Radium (226 + 228)7% of 14 local samples were above the limit.
- Manganese5% of 772 local wells tested were above the New Jersey nuisance level.
- PFOA4% of 141 local wells tested were above the New Jersey limit.
- PFOS1% of 141 local wells tested were above the New Jersey limit.
Contamination sources on record in Hopewell township
NJDEP records 26 regulated sites in Hopewell township, among 26 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.
- 23
- registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
- 1
- lined landfill or transfer facility
- 2
- other remediation projects
Treatment that fits the local profile
- Nitrate
- Point-of-use reverse osmosis; Anion exchange; Distillation
- Total coliform
- Inspect and repair the well cap and casing, then shock chlorinate and retest; UV disinfection whole-house; Chlorination system
- 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
- Radium (226 + 228)
- Water softener (cation exchange); Point-of-use reverse osmosis
Get your Hopewell township water tested at home
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Common questions
Is there arsenic in well water in Hopewell township?
Arsenic was detected in 15% of 20 public well samples in Hopewell 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 Hopewell township?
The median radon level across 5 public samples in Hopewell township was 340 pCi/L, with a high of 1,900 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Hopewell 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: 48 samples in Hopewell 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 10 contaminants in Hopewell township, up to 772 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: 26 regulated sites located in Hopewell 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.