New Jersey has 21 counties, with 7 classified as EPA Zone 1 (highest risk). With an average radon level of 5.93 pCi/L, New Jersey state testing data reveals significantly elevated risks across multiple counties. Testing is highly recommended.
New Jersey is the fourth smallest state in terms of size, and yet it’s the 11th most populous. It also happens to be the most densely populated state in the country.
New Jersey does have an active radon program, dedicated to educating citizens about the risks associated with the deadly gas. You can find more information on Radon, testing and mitigation at the official page.
Explore radon data organized by metro region, including average levels, hotspot cities, and local mitigation professionals.
Cities with the most user-submitted radon test data, ranked by number of submissions.
| City | Avg User Radon Level | Submissions |
|---|---|---|
| Cherry Hill | 6.44 pCi/L | 9 |
| Hillsborough | 6.14 pCi/L | 7 |
| Freehold | 10.50 pCi/L | 6 |
| Marlboro | 6.17 pCi/L | 6 |
| Bernardsville | 7.00 pCi/L | 5 |
| Phillipsburg | 7.00 pCi/L | 5 |
| Edison | 5.60 pCi/L | 5 |
| Princeton | 5.40 pCi/L | 5 |
| Sussex | 9.75 pCi/L | 4 |
| Piscataway | 6.75 pCi/L | 4 |
| Caldwell | 5.00 pCi/L | 4 |
| Atlantic Highlands | 4.75 pCi/L | 4 |
| West Orange | 4.00 pCi/L | 4 |
| Basking Ridge | 3.75 pCi/L | 4 |
| Hackettstown | 3.75 pCi/L | 4 |
| Livingston | 3.25 pCi/L | 4 |
| Nutley | 3.25 pCi/L | 4 |
| Sicklerville | 7.00 pCi/L | 3 |
| Clifton | 6.00 pCi/L | 3 |
| Westfield | 6.00 pCi/L | 3 |
All 21 New Jersey counties with their EPA radon zone classification and user-submitted average radon levels.
Browse radon data for individual cities across New Jersey. Each city page includes user-submitted radon levels, local contractors, and mitigation resources.