Radon is the second-leading cause of lung cancer in the U.S. Certified testing tells you your home's number; certified mitigation brings it down.
RadonList is built directly from the NJDEP Radon Certification Program — the official list of who is actually certified to do this work. No pay-to-play rankings.
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29 certified companies · browse by county
Every listing comes from the NJDEP Radon Certification Program — the government's own certification records.
See each company's certification categories and license number, with a link to verify at the source.
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New Jersey requires businesses that test for or mitigate radon to be certified by the NJDEP Radon Program — separate certifications for measurement and mitigation.
What to check before closing on a New Jersey home with an existing radon system — the paperwork the seller owes you, reading the manometer, when to retest, and fan lifespan.
How NJDEP's radon potential map assigns every New Jersey municipality to Tier 1, 2, or 3, which counties run high, and why a Tier 3 address still needs a test.
What New Jersey law actually requires about radon in a home sale, how buyer-side testing works, and how elevated results typically get negotiated and resolved.
What a radon mitigation system costs in New Jersey in 2026 — typical price ranges, what drives quotes up, operating costs, and how to verify the system actually worked.
What radon testing costs in New Jersey — DIY charcoal kits vs professional continuous monitors, free county kit programs, and when state rules require a certified tester.
When radon in well water matters in New Jersey, what the Private Well Testing Act does and doesn't require, the 10,000-to-1 water-to-air rule, and what aeration vs GAC treatment costs.
Radon is a naturally occurring radioactive gas that seeps into buildings from soil. It is the second-leading cause of lung cancer in the United States after smoking. The EPA action level is 4.0 pCi/L — at or above that, mitigation is recommended.
New Jersey requires radon testing and mitigation businesses to be certified by the NJDEP Radon Program — measurement and mitigation are separate certifications. Every company in this directory appears in the official certification list.
A professional radon test in NJ typically costs about $100–$300. If levels are high, a mitigation system usually runs about $800–$2,500 installed, depending on the home’s foundation.
NJDEP assigns every New Jersey municipality a radon potential tier: Tier 1 (high), Tier 2 (moderate), or Tier 3 (low). Northwestern and central NJ have many Tier 1 towns — but elevated radon can occur in any home, so testing is the only way to know.
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