Radon levels in New Jersey: Low
The model predicts a population-weighted basement average of 1.3 pCi/L across New Jersey's 21 counties - about 27% below the US average of 1.8 pCi/L. Above-ground floors average 0.8 pCi/L.
Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. How the numbers work.
7 / 21
EPA Zone 1 counties (33%)
11 / 3
Zone 2 / Zone 3 counties
0
counties predicted ≥ 4 pCi/L
0%
of ZIP codes predicted ≥ 4 pCi/L
New Jersey counties by predicted radon
Sorted highest to lowest predicted basement average. 21 counties.
| County | Predicted basement | Upstairs | Grade | EPA zone | ZIPs |
|---|---|---|---|---|---|
| Warren County | 2.3 pCi/L | 1.6 | Moderate | EPA Zone 1 | 10 |
| Sussex County | 2.3 pCi/L | 1.6 | Moderate | EPA Zone 1 | 18 |
| Hunterdon County | 2.1 pCi/L | 1.6 | Moderate | EPA Zone 1 | 17 |
| Morris County | 1.8 pCi/L | 1.1 | Low | EPA Zone 1 | 44 |
| Somerset County | 1.7 pCi/L | 1.2 | Low | EPA Zone 1 | 23 |
| Salem County | 1.4 pCi/L | 0.8 | Low | EPA Zone 2 | 7 |
| Cape May County | 1.4 pCi/L | 0.7 | Low | EPA Zone 3 | 13 |
| Mercer County | 1.3 pCi/L | 0.9 | Low | EPA Zone 1 | 20 |
| Middlesex County | 1.3 pCi/L | 0.9 | Low | EPA Zone 2 | 36 |
| Gloucester County | 1.3 pCi/L | 0.8 | Low | EPA Zone 2 | 23 |
| Burlington County | 1.3 pCi/L | 0.8 | Low | EPA Zone 2 | 28 |
| Monmouth County | 1.3 pCi/L | 0.8 | Low | EPA Zone 1 | 48 |
| Cumberland County | 1.3 pCi/L | 0.7 | Low | EPA Zone 2 | 13 |
| Union County | 1.3 pCi/L | 0.7 | Low | EPA Zone 2 | 26 |
| Atlantic County | 1.2 pCi/L | 0.7 | Low | EPA Zone 3 | 23 |
| Ocean County | 1.2 pCi/L | 0.7 | Low | EPA Zone 3 | 28 |
| Passaic County | 1.2 pCi/L | 0.7 | Low | EPA Zone 2 | 27 |
| Bergen County | 1.2 pCi/L | 0.7 | Low | EPA Zone 2 | 66 |
| Essex County | 1.2 pCi/L | 0.6 | Low | EPA Zone 2 | 31 |
| Camden County | 1.1 pCi/L | 0.7 | Low | EPA Zone 2 | 33 |
| Hudson County | 1.0 pCi/L | 0.5 | Low | EPA Zone 2 | 15 |
New Jersey radon questions
- Is radon high in New Jersey?
- New Jersey's population-weighted predicted basement average is 1.3 pCi/L, about 27% below the US average of 1.8. 0 of its 21 modeled counties are predicted at or above the EPA action level of 4 pCi/L, 3 are in the 2-4 "consider fixing" range and 18 are below 2. 0% of New Jersey ZIP codes are predicted at 4 or higher.
- Which New Jersey county has the highest radon?
- Warren County has the highest predicted basement average in New Jersey at 2.3 pCi/L (EPA Zone 1). The lowest is Hudson County at 1.0 pCi/L. These are modeled area averages; individual homes in any county can test far higher.
- How many EPA Zone 1 counties are in New Jersey?
- 7 of New Jersey's 21 counties (33%) are EPA Zone 1 (highest potential), 11 are Zone 2 and 3 are Zone 3. The EPA zone map dates from 1993; the predicted values on this page come from a 2001-2021 model built on millions of actual tests, so the two can disagree for a given county.
- Should I test for radon in New Jersey?
- Yes. Even though New Jersey's predicted average is below 2 pCi/L, the EPA recommends every home be tested - radon varies house to house, and 10.4% of New Jersey ZIP codes are still predicted at 2 pCi/L or higher.
New Jersey radon program
Many states offer free or discounted test kits and keep lists of certified mitigators. Find the New Jersey radon office through the EPA state radon contacts page. Then read how to test and what mitigation costs.