Locations and reports
Radon Levels in New Jersey
What this means for you
- Your area: EPA rates 7 of New Jersey's 21 classified counties Zone 1, the highest of its three radon zones. Zones are predictions for whole counties, and homes with elevated levels occur in all three zones.
- Local tests: CDC publishes New Jersey's radon test results by county. Open your county below to see its figures.
- Your home: The only way to know your home’s level is to test it.
pCi/L (picocuries per liter) is the unit radon is measured in. EPA recommends fixing a home at 4 pCi/L or above, its action level.
For New Jersey, EPA's Map of Radon Zones places 7 of its 21 classified counties in Zone 1, highest predicted potential, a prediction for each county as a whole. Radon levels vary from home to home, so only a test measures the level in yours.
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 describes predicted potential across a whole county. It is not intended to determine whether any individual home should be tested, and homes with elevated levels occur in all three zones. EPA recommends testing every home regardless of zone, and testing is the only way to know the radon level in a specific building.
This is a county-level geologic prediction. It is not a measurement of any address, and houses with elevated radon are found in all three zones.
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
CDC publishes New Jersey's radon test figures by county: 21 of its 21 counties have one. Each county's share is in the county list.
New Jersey, In figures
New Jersey in figures
What the published data says about New Jersey, in words. A zone and a share of tests describe an area, never the level in any one home.
Predicted
PredictedEPA places 7 of New Jersey's 21 counties in Zone 1, 11 in Zone 2 and 3 in Zone 3.
Zone 1 counties, A to Z, begin with Hunterdon County, Mercer County and Monmouth County; the county section below lists all 7.
Compared
Calculated by Radon41133% of New Jersey's counties with a zone on file are in Zone 1, a smaller share than across all U.S. counties (34%). It is a share of counties, not of land, people or homes.
Reported tests
MeasuredCDC has no statewide testing figure for New Jersey on file here.
21 of the 21 counties have a published county figure; the most tests in each one's latest year were reported for Bergen County (7,647 in 2022), Middlesex County (6,221 in 2022) and Morris County (6,182 in 2022).
Local record
New Jersey's radon program is the Radon Section, run by New Jersey Department of Environmental Protection; its contacts are under Local resources.
2 cities have a page setting the figures of the counties it lies in side by side: Freehold and Trenton.
New Jersey, Counties
New Jersey counties by EPA zone
PredictedAll 21 counties, by the zone EPA predicts for each. Every county has its own report.
Zone 1: highest predicted potential7
- Hunterdon County21.1% of reported tests at or above 4 pCi/L, 2022
- Mercer County10.6% of reported tests at or above 4 pCi/L, 2022
- Monmouth County9.8% of reported tests at or above 4 pCi/L, 2022
- Morris County13.6% of reported tests at or above 4 pCi/L, 2022
- Somerset County15.4% of reported tests at or above 4 pCi/L, 2022
- Sussex County22.3% of reported tests at or above 4 pCi/L, 2022
- Warren County24.6% of reported tests at or above 4 pCi/L, 2022
Zone 2: moderate predicted potential11
- Bergen County6.1% of reported tests at or above 4 pCi/L, 2022
- Burlington County6.2% of reported tests at or above 4 pCi/L, 2022
- Camden County6.7% of reported tests at or above 4 pCi/L, 2022
- Cumberland County8.6% of reported tests at or above 4 pCi/L, 2022
- Essex County4.1% of reported tests at or above 4 pCi/L, 2022
- Gloucester County12.2% of reported tests at or above 4 pCi/L, 2022
- Hudson County3.4% of reported tests at or above 4 pCi/L, 2022
- Middlesex County7.3% of reported tests at or above 4 pCi/L, 2022
- Passaic County7.5% of reported tests at or above 4 pCi/L, 2022
- Salem County10.8% of reported tests at or above 4 pCi/L, 2022
- Union County5.1% of reported tests at or above 4 pCi/L, 2022
New Jersey, Cities
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.
New Jersey, Local resources
Local resources in New Jersey
Who to ask in New Jersey: the state's radon program, test kits and professionals.
Radon Section
New Jersey Department of Environmental Protection
New Jersey’s radon program answers questions about testing, mitigation and the rules where you live.
- 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.
Test kits
The program says: Check with your municipal or county health department for free radon test kits or purchase a test kit from a hardware store or a NJ certified radon business.
Radon professionals
45 professionals are listed in New Jersey.
Professionals in New JerseyNew Jersey, Questions
Questions about radon in New Jersey
Common questions9 questions, answered from the figures above
Is radon a problem in New Jersey?
EPA's Map of Radon Zones places 7 of the 21 New Jersey counties it classifies in Zone 1, the highest predicted potential, 11 in Zone 2 and 3 in Zone 3. An EPA radon zone describes predicted potential across a whole county. It is not intended to determine whether any individual home should be tested, and homes with elevated levels occur in all three zones. EPA recommends testing every home regardless of zone, and testing is the only way to know the radon level in a specific building.
Who does radon mitigation in New Jersey?
Radon411's New Jersey directory lists 45 certified radon companies. EPA recommends having a qualified contractor fix a home with a radon problem, because lowering high radon levels takes technical knowledge and special skills, and some states require the work to be done by a licensed or certified professional.
How radon mitigation worksWhat mitigation costsRadon professionals in New Jersey
How do I get a radon test in New Jersey?
EPA says you can test your home yourself or hire a qualified radon test company, and that either approach takes only a small amount of time and effort. The New Jersey radon program is the place to ask about certified testers and any test kit offer it runs.
How to test a homeFree and low-cost kits by stateNew Jersey radon program
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. Zone 1 is EPA's class for highest predicted potential, a predicted average indoor screening level greater than 4 pCi/L. A zone is a prediction for a county, not a measurement of any home.
Radon in Hunterdon CountyRadon in Mercer CountyRadon in Monmouth County
Which New Jersey counties have the highest radon?
21 of New Jersey's 21 counties have an EPA radon zone published here. Radon411 will not rank counties on data it does not hold, and a zone is a prediction for an area rather than a measurement of any building.
What share of radon tests in New Jersey are high?
CDC has published no statewide radon testing statistics for New Jersey, so we cannot give a figure. Where CDC does publish one, the percentage describes radon tests reported to CDC, not homes.
Which EPA region is New Jersey in?
New Jersey is in EPA Region 2: New Jersey, New York, Puerto Rico, U.S. Virgin Islands.
Do I need to test my home in New Jersey?
Yes, wherever you live in the state. Testing is the only way to know the radon level in a specific building. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L.
Why does this page show coverage rather than one radon level for New Jersey?
A statewide figure averages counties with very different geology and very different numbers of reported tests, so it hides more than it shows. The county report is the level at which the EPA zone, the geologic potential and the reported testing statistics are actually published, which is why the county table above links to every one of them.
What these figures mean if you own, buy, sell or rent
The zone counts on this page describe counties across New Jersey. They are predictions for areas, and none of them measures your building.
- How to test a home
If you own your home
Test the lowest lived-in level; a short-term kit screens in days, a long-term kit reflects the year.
- Buying a house: radon guide
If you are buying
Ask for past results and any system's post-mitigation test, and test during the sale.
- Selling a house: radon guide
If you are selling
Testing before you list puts the timing in your hands; disclosure rules differ by state.
- Radon in rental homes
If you rent, or rent out a home
A tenant can test; a fix is the owner's to make, and duties differ by state.
How long a test has to run, under what conditions, and what EPA says a result means: the testing standard, in full.
New Jersey, Products
Testing and mitigation products
Whatever the figures for New Jersey show, only a test tells you about one home.
Testing
- Short-term test kitsPassive detectors exposed for a few days under closed-building conditions, then analyzed by a lab.
- Long-term test kitsDetectors exposed for more than 90 days, for a closer picture of the annual average.
- Continuous monitorsPowered devices that log radon on a repeating cycle, often used for transaction tests.
- Digital detectorsConsumer devices that display a running radon reading without a lab.
- Water radon testsKits for radon dissolved in well water, analyzed by a lab.
Mitigation
- Mitigation fansThe inline fan that keeps a soil depressurization system running, sized by the installer.
- System indicatorsU-tube manometers and fan alarms that show whether a mitigation system is still working.
- Sealing materialsCrack, joint and sump sealing used alongside a mitigation system, not instead of one.
New Jersey / Next steps
What to do next
Learn
Know what radon is
What radon is, how it gets indoors, and why a county zone is not a reading for your home.
Learn about radonTest
Test the building you live in
Short-term or long-term, where the device goes, and closed-house conditions.
How to testFix
Bring a high level down
How a mitigation system works, and the retest that confirms it.
How mitigation worksFind a pro
Hire a certified professional
Measurement and mitigation professionals by state, with their certifications.
Find a professional
Informational. Follow EPA guidance. EPA says all radon tests should be taken for a minimum of 48 hours, with windows and doors closed from 12 hours before a short-term test.