Radon in New Jersey: radon map by county
EPA's Map of Radon Zones puts 7 of New Jersey's 21 counties in Zone 1 (predicted average indoor radon above 4 pCi/L), 11 in Zone 2 and 3 in Zone 3.
Radon by county in New Jersey
| County | EPA zone | Lab tests | Median | 4+ pCi/L |
|---|---|---|---|---|
| Atlantic County | Zone 3 | n/a | n/a | n/a |
| Bergen County | Zone 2 | n/a | n/a | n/a |
| Burlington County | Zone 2 | n/a | n/a | n/a |
| Camden County | Zone 2 | n/a | n/a | n/a |
| Cape May County | Zone 3 | n/a | n/a | n/a |
| Cumberland County | Zone 2 | n/a | n/a | n/a |
| Essex County | Zone 2 | n/a | n/a | n/a |
| Gloucester County | Zone 2 | n/a | n/a | n/a |
| Hudson County | Zone 2 | n/a | n/a | n/a |
| Hunterdon County | Zone 1 | n/a | n/a | n/a |
| Mercer County | Zone 1 | n/a | n/a | n/a |
| Middlesex County | Zone 2 | n/a | n/a | n/a |
| Monmouth County | Zone 1 | n/a | n/a | n/a |
| Morris County | Zone 1 | n/a | n/a | n/a |
| Ocean County | Zone 3 | n/a | n/a | n/a |
| Passaic County | Zone 2 | n/a | n/a | n/a |
| Salem County | Zone 2 | n/a | n/a | n/a |
| Somerset County | Zone 1 | n/a | n/a | n/a |
| Sussex County | Zone 1 | n/a | n/a | n/a |
| Union County | Zone 2 | n/a | n/a | n/a |
| Warren County | Zone 1 | n/a | n/a | n/a |
Lab tests: buildings tested by radon laboratories, 2008 to 2017; median in pCi/L; “4+ pCi/L” is the share of tests at or above EPA's action level. n/a: no value on file (no tests, or too few to report).
What the zones mean
Zone 1 counties have a predicted average indoor radon screening level above 4 pCi/L, Zone 2 from 2 to 4 pCi/L and Zone 3 below 2 pCi/L. The prediction is from 1993 indoor measurements, geology, aerial radioactivity, soils and foundation types. EPA: “This map should not be used to determine if individual homes need to be tested.” EPA recommends fixing a home at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, because there is no known safe level of exposure.
Radon in New Jersey: questions
What radon zone is New Jersey?
EPA's 1993 map does not give states one zone; it zones each county. In New Jersey, 7 counties are Zone 1, 11 Zone 2 and 3 Zone 3. EPA says the map "should not be used to determine if individual homes need to be tested".
Does New Jersey publish its own radon test data?
New Jersey's radon program reports county test results; the latest year with county results is 2022, shown on each county page.
Should I test for radon in New Jersey?
Yes. EPA recommends testing every home no matter where it is, fixing it at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, because there is no known safe level of radon exposure.
States bordering New Jersey
Other free hazard lookups
- Radon by county and ZIP codeEPA radon zone and the radon test results on file for any county, ZIP code or address.
- Fault lines near an addressUSGS-mapped earthquake faults within 5 miles, their age and slip rate, and the USGS seismic hazard value.
- Power lines near an addressHigh-voltage transmission lines within 1 mile from federal maps, with voltage and distance.
- Flood zone lookupThe FEMA flood zone mapped at any US address. Not an official flood zone determination.
- Superfund sites near an addressThe nearest EPA Superfund (NPL) sites and their status.
All of these, plus wetlands, FEMA hazard ratings and the federal contamination lists, are in the Environmental Records Report for any US address ($29).
Superfund sites in New Jersey · Radon map of every state
Data compiled 2026-10-20. County-level screening information, not a radon measurement of any building.