New Jersey well water results by county
New Jersey is one of the few places where well tests at home sales are reported to the state. NJDEP publishes the share of tested wells over each standard, by county (Sept 2002 to Dec 2024). Pick your county for the full table.
| County | Arsenic over 5 µg/L | Gross alpha over 15 pCi/L | Nitrate over 10 mg/L | Fecal coliform / E. coli present |
|---|---|---|---|---|
| Atlantic County | 0.1% | 11.2% | 3.1% | 0.5% |
| Bergen County | 9.5% | 1.9% | 0.7% | 1.1% |
| Burlington County | 0.3% | 10% | 1.1% | 0.7% |
| Camden County | 0% | 36.3% | 1.5% | 0.5% |
| Cape May County | 0.3% | 1.1% | 2.3% | 0.8% |
| Cumberland County | 0.5% | 30.6% | 12.9% | 0.6% |
| Essex County | 11.3% | 0% | 0.9% | 0% |
| Gloucester County | 0.3% | 12.8% | 2.7% | 0.6% |
| Hunterdon County | 15.7% | 5.8% | 0.8% | 3.3% |
| Mercer County | 17.9% | 5.9% | 1.5% | 3% |
| Middlesex County | 3.9% | 12.9% | 3.3% | 2.1% |
| Monmouth County | 0.4% | 2.2% | 0.5% | 0.8% |
| Morris County | 1.8% | 4.2% | 1.8% | 1.9% |
| Ocean County | 0.2% | 5.3% | 0.5% | 0.8% |
| Passaic County | 1.1% | 12.1% | 3.9% | 3% |
| Salem County | 0.3% | 17.4% | 8.8% | 0.8% |
| Somerset County | 16.2% | 7.5% | 0.4% | 4.1% |
| Sussex County | 1.9% | 12.1% | 3.3% | 3.5% |
| Warren County | 1.9% | 5.8% | 2.4% | 2.9% |
Hudson and Union counties are not shown: too few wells were sampled for a reliable county figure. 'Testing is not required' means the state doesn't require that test in the county.
Find a certified lab: New Jersey labs. Also see all county pages.
Questions
Which New Jersey counties have the most arsenic in wells?
In NJDEP's 2002–2024 data, the highest shares of wells over 5 µg/L were in Mercer, Somerset, Hunterdon, Essex and Bergen counties.
Which counties have the most gross alpha radioactivity?
Camden and Cumberland counties had the highest shares of wells over 15 pCi/L, followed by Salem, Middlesex and Gloucester.