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New Jersey Radon Map and Levels by County

New Jersey's counties span all three EPA radon zones. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    11.7%

    13.8 pts below U.S.

    New Jersey
    11.7%
    U.S.
    25.5%

    130,190 tests across 21 counties, 2020

  • Rank among states

    17 of 18

    Ten lowest states

    New Jersey
    11.7%
    Nebraska
    42.2%

    By share, every state pooled the same way, 2020

  • Counties in EPA Zone 1

    7 of 21

    Some at highest potential

    Zone 1
    7
    Zone 2
    11

    Most counties sit in Zone 2; Zone 1 is the highest potential

  • Highest county

    28.1%

    Warren County

    Warren
    28.1%
    Cape May
    0.0%

    Counties with 30+ tests, 2020

Read a result for New Jersey

Starts at EPA's action level

4.0pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 4.0 pCi/L

At or above 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. 11.7% of New Jersey's reported tests reached 4 pCi/L, 2020.

Interpret this readingWhat a fix costs

The data

New Jersey, At a glance

New Jersey at a glance

Predicted: EPA radon zone

21 of 21 counties classified

EPA classifies counties, not states. Of the 21 counties in New Jersey with a zone, 7 are in Zone 1, 11 in Zone 2 and 3 in Zone 3.

  • Zone 1: Highest predicted potentialgreater than 4 pCi/L7 of 21 counties · 33.3%
  • Zone 2: Moderate predicted potential2 to 4 pCi/L11 of 21 counties · 52.4%
  • Zone 3: Lower predicted potentialless than 2 pCi/L3 of 21 counties · 14.3%

An EPA radon zone predicts a whole county. It is not intended to determine whether any individual home should be tested: homes with elevated levels occur in all three zones, and EPA recommends testing every home regardless of zone.

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

CDC test figures, county by county

CDC publishes New Jersey's radon test figures by county: 21 of its 21 counties have one. Each one's share is in the county list.

How to read these figures

New Jersey, Compared

New Jersey radon figures, compared

Calculated by Radon411
New Jersey, 2020
11.7%
of 130,190 tests at or above 4 pCi/L, pooled
Against the U.S.
−13.8points
25.5% pooled
Rank among the states
17 of 18
1 is the highest share
Counties with 30 or more tests
21
Highest
28.1%
Warren County
Lowest
0.0%
Cape May County

Fewer reported tests reach 4 pCi/L in New Jersey than in most states: 11.7% of 130,190 in 2020, from 21 counties. Nationally the pooled share is 25.5%: 13.8 points higher than here. Among 18 states pooled the same way it ranks 17th, with Alaska (15.9%) above it and Louisiana (0.8%) below.

Warren County reports the highest share (28.1% of 3,473 tests) and Cape May County the lowest (0.0%); the most tests came from Bergen County, 13,839 of them at 7.5%. EPA's 1993 map puts 7 of its 21 classified counties in Zone 1; against that, 11.7% of the tests reported since reached 4 pCi/L.

By band, 5 counties at 15% to 30%, 13 counties at 5% to 15%, 3 counties at under 5%. Year by year (9 years pooled), the share went from 12.8% (2014) to 9.7% (2022), down 3.1 points, with 2014 the highest at 12.8%.

New Jersey ranked among 18 states by pooled share of tests at or above 4 pCi/L, 2020
StateRankCountiesTestsAt or above 4 pCi/L
Pennsylvania8 of 186793,66930.3%
Wisconsin9 of 187218,65027.0%
Florida10 of 184812,19823.2%
New York11 of 18602,27322.7%
North Carolina12 of 189011,51121.1%
Washington13 of 18372,78119.0%
Oregon14 of 18335,35216.8%
Vermont15 of 18142,29616.5%
Alaska16 of 181059115.9%
New Jersey17 of 1821130,19011.7%
Louisiana18 of 18181,7760.8%
New Jersey's highest and lowest counties with 30 or more tests, by share at or above 4 pCi/L, 2020
CountyRankTestsAt or above 4 pCi/L
Warren County1 of 213,47328.1%
Hunterdon County2 of 214,68325.7%
Sussex County3 of 215,76324.3%
Somerset County4 of 218,68517.6%
Morris County5 of 2112,53915.4%
Mercer County6 of 216,04613.6%
Gloucester County7 of 214,45313.5%
Salem County8 of 2153112.6%
Monmouth County9 of 2111,80311.2%
Passaic County10 of 216,0229.6%
Cape May County21 of 212060.0%
Hudson County20 of 213,0003.6%
Ocean County19 of 213,4473.8%
Essex County18 of 2110,4535.7%
Burlington County17 of 216,7857.0%
New Jersey's counties with 30 or more tests, by their own share at or above 4 pCi/L, 2020
ShareCountiesTheir testsFor example
50% or more00None
30% to 50%00None
15% to 30%535,143Warren County, Hunterdon County, Sussex County
5% to 15%1388,394Mercer County, Gloucester County, Salem County
Under 5%36,653Ocean County, Hudson County, Cape May County
New Jersey pooled by year, against the United States
YearCountiesTestsAt or above 4 pCi/LUnited StatesChange from the row before
202221108,9349.7%23.9%−0.6 points
202121125,53710.3%24.4%−1.4 points
202021130,19011.7%25.5%+0.5 points
201921109,12611.2%29.0%+0.2 points
201821105,54811.0%29.1%−0.9 points
201721104,85711.9%31.7%−0.6 points
20162196,68212.5%31.2%Level
20152188,72212.5%35.5%−0.2 points
20142181,08312.8%34.9%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period. CDC publishes no state or national figure.

New Jersey, Counties

New Jersey counties by EPA zone

Predicted

All 21 counties, grouped by the zone EPA predicts and ordered by their reported share at or above 4 pCi/L, under New Jersey's map. Each county has a page of its own.

New Jersey radon map by county: EPA radon zones. Map of New Jersey's 21 counties shaded by EPA radon zone: Zone 1 in red-orange, Zone 2 in amber, Zone 3 in pale sand. 7 in Zone 1, 11 in Zone 2, 3 in Zone 3.
New Jersey radon map by countyEPA radon zones for New Jersey's counties: 7 counties in Zone 1, 11 counties in Zone 2, 3 counties in Zone 3.A prediction for each county, not a reading of any home; elevated homes occur in all three zones.

The 12 highest in New Jersey, 2020

Zone 1: highest predicted potential7

Local help

New Jersey, Local resources

Local resources in New Jersey

Who to ask in New Jersey: its radon program, test kits and professionals.

What New Jersey's program says
Phone
800-648-0394
Licensing of radon professionals
By law, all businesses and professionals conducting radon testing and mitigation in New Jersey must be certified by the DEP.
Disclosure when a home is sold or rented
Under the law, the seller must provide the buyer, at the time the contract of sale is entered into, with a copy of the results of the radon test and evidence of any mitigation or treatment.

What it means

New Jersey, Questions

Questions about radon in New Jersey

Is radon a problem in New Jersey?

Of the 21 counties in New Jersey that EPA's Map of Radon Zones classifies, 7 carry Zone 1 (the highest predicted potential), 11 Zone 2 and 3 Zone 3. Pooled from 21 counties, 11.7% of the 130,190 radon tests reported to CDC in 2020 were at or above 4 pCi/L, 17th of 18 states.

Who does radon mitigation in New Jersey?

Radon411's New Jersey directory lists 15 radon businesses for testing, mitigation or both, each with the licensing list it was read from.

Which New Jersey counties are in EPA radon Zone 1?

7 counties are in Zone 1: Hunterdon County, Mercer County, Monmouth County, Morris County, Somerset County, Sussex County, Warren County.

Which New Jersey counties have the highest radon?

By the share of reported tests at or above 4 pCi/L, 2020: Warren County 28.1% (3,473 tests), Hunterdon County 25.7% (4,683 tests), Sussex County 24.3% (5,763 tests), Somerset County 17.6% (8,685 tests), Morris County 15.4% (12,539 tests).

Which EPA region is New Jersey in?

New Jersey is in EPA Region 2: New Jersey, New York, Puerto Rico, U.S. Virgin Islands.

Products

New Jersey, Products

Testing a home in New Jersey

11.7% of the 130,190 tests reported to CDC for New Jersey in 2020 reached 4 pCi/L: a short-term kit (2 to 90 days) gives a first answer in days, a long-term test the year-round average. A short-term kit (2 to 90 days) is the quick first check for a home in New Jersey; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for New Jersey homes, compared

Explore

Cities in New Jersey with their own page

Radon data is published by county, not by city. Each city page sets the figures of the counties the city lies in side by side.