Radon rules differ by state. Here is how.
There is no federal radon contractor licence. Credentialing, disclosure, and new-construction requirements are state matters, and the ten states we serve handle them in materially different ways — which changes what you verify before hiring and what a seller is actually obliged to tell you.
Each centre names the agency that answers a question rather than restating operational details we cannot re-verify. That is a deliberate accuracy trade, explained on our methodology page.
States that credential radon work
A state licence or certification exists, so verification means confirming a number with the issuing agency — and confirming it covers mitigation rather than measurement alone.
- Illinois — Statewide IEMA-OHS licensing, a radon-specific disclosure statute, and how to verify both.
- Iowa — State health department certification, disclosure on the residential form, and consistently elevated results.
- Nebraska — State credentialing, radon-resistant new construction requirements, and negotiated remedies.
- Minnesota — A genuine state licence through MDH, plus a disclosure statute that acts before signing.
- Ohio — A genuine state licence covering testers, contractors, and labs — and a disclosure form that asks directly.
- Pennsylvania — DEP certification is mandatory for radon services, and elevated results are common enough to expect.
- Kentucky — State licensing through public health, plus karst geology that makes neighbourhood inference especially unreliable.
States without a radon licence
No state register exists, so national certification through NRPP or NRSB is the credential, and the written scope and warranty carry more weight.
- Wisconsin — No state licence — national certification is the credential, and documentation carries more weight.
- Michigan — No state licence — verify national certification, and read the written scope harder.
- Colorado — No state licence, but a required warning statement before a sale — and a testing quirk worth knowing.
Related resources
- Who licenses radon work in the ten states we serve — the standing reference behind these pages.
- How state radon certification differs — what a credential actually means for a homeowner.
- For radon contractors — what we verify before a request routes to a business.
- All markets — the metros and cities we cover.
Get quotes from credentialed local contractors
Free to request and no obligation. We verify credentials with the issuing authority before any request routes to a contractor.