Radon Pros in New Jersey

Last updated: March 2026

Northern New Jersey sits on the Reading Prong geological formation, one of the highest-radon areas in the entire United States. Hunterdon, Somerset, Morris, Warren, and Sussex counties consistently produce some of the most elevated indoor radon readings in the country, with individual homes frequently testing above 20 pCi/L. These areas are firmly EPA Zone 1. Central and southern New Jersey transition to Zone 2 and Zone 3, with the Pine Barrens and shore communities generally showing lower levels. New Jersey has one of the strongest radon regulatory frameworks in the nation — the NJ DEP requires all radon testers and mitigators to be certified, with the state maintaining its own certification examination beyond national NRPP requirements. In real estate transactions, radon testing is not mandated by state law, but it is extremely common in northern NJ transactions, and many municipalities have local disclosure requirements. New Jersey is distinctive because the Reading Prong affects the most densely populated portion of the state, meaning a large number of residents live in Zone 1 areas. The NJ DEP maintains an active radon program with public outreach, free test kit programs, and detailed county-level data. The EPA recommends all New Jersey homes be tested, with particular emphasis on the northern counties where geological conditions produce consistently high readings.