New Jersey has one of the most comprehensive state radon programs in the United States. The New Jersey Department of Environmental Protection (NJDEP) has administered an active radon program since the 1980s — driven partly by New Jersey’s historic role in radon risk discovery (the Stanley Watras case that put radon on the national map occurred in Boyertown, Pennsylvania, but the Reading Prong geological formation extends into New Jersey, creating similarly high radon potential). New Jersey has enacted both contractor licensing and school radon testing requirements.
EPA Radon Zone Designation
New Jersey counties range from Zone 1 in the northern portion of the state to Zone 2 in central and southern New Jersey. The highest-radon area in New Jersey is the northern region overlying the Reading Prong geological formation — specifically Morris, Somerset, Hunterdon, Warren, and Sussex counties — where average indoor radon levels are among the highest in the northeastern U.S. Bergen, Passaic, and Essex counties also show significant radon levels.
Radon Contractor Licensing in New Jersey
New Jersey has a comprehensive radon contractor licensing program administered by the NJDEP. New Jersey law requires radon contractors to hold a New Jersey state radon license — separate from and in addition to NRPP or NRSB national certification. New Jersey licensing requires passing the state radon contractor examination, maintaining liability insurance, and completing continuing education requirements. The NJDEP maintains a searchable online database of licensed radon professionals. Performing radon measurement or mitigation without a New Jersey license is a violation of state law.
Radon Disclosure Requirements in New Jersey
New Jersey requires sellers of residential real property to complete a Seller’s Property Disclosure Statement that includes questions about radon — whether the property has been tested, what the results were, and whether a radon mitigation system is installed. New Jersey sellers must disclose known radon test results. Radon testing is standard practice in New Jersey real estate transactions, particularly in northern Zone 1 counties. The NJDEP also requires distribution of the EPA radon pamphlet in certain transaction contexts.
School and Public Building Radon Testing in New Jersey
New Jersey requires radon testing in public schools and has specific provisions for childcare facilities. The New Jersey Department of Education and NJDEP have coordinated school radon testing programs. Results are reported to parents. New Jersey is among the states with the most active school radon testing programs in the northeastern U.S.
Frequently Asked Questions
Does New Jersey require radon contractor licensing?
Yes. New Jersey has a comprehensive state licensing program requiring contractors to hold a New Jersey radon license in addition to NRPP or NRSB certification. Verify license status through the NJDEP radon program before hiring.
What parts of New Jersey have the highest radon?
Northern New Jersey counties overlying the Reading Prong geological formation — Morris, Somerset, Hunterdon, Warren, and Sussex counties — have the highest radon potential in the state. Bergen, Passaic, and Essex counties also show elevated levels.
Does New Jersey require radon disclosure when selling a home?
Yes. The New Jersey Seller’s Property Disclosure Statement requires disclosure of known radon test results and the presence of any mitigation system.
New Jersey Radon Data and County Survey
The New Jersey Department of Environmental Protection has conducted comprehensive county-level radon surveys. Morris County consistently shows some of the state’s highest average indoor radon concentrations, reflecting the Reading Prong granite beneath the county. Somerset, Hunterdon, and Warren counties in the northwestern corner of the state also show very high averages. Sussex County in the northernmost corner of NJ has the state’s highest elevation and most concentrated granitic geology. The NJDEP’s online county radon data is one of the most complete state-level radon databases in the Northeast.
New Jersey Radon in Real Estate: Practical Context
New Jersey’s real estate market moves fast — inspection periods are often compressed to 7–10 days. This means radon testing must be ordered immediately when the inspection contingency period begins. Professional continuous radon monitors are commonly used in NJ real estate transactions because they produce results within 48–96 hours without the 3–7 day mail-to-lab turnaround of charcoal canisters. Many NJ home inspectors offer radon testing add-ons precisely because of the timing pressure. Buyers should confirm the testing timeline and device type before signing a contract.
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