Who licenses radon work in the ten states we serve
There is no federal radon contractor licence. Credentialing is a state matter, and the ten states this platform serves do it in three materially different ways — which means the answer to "is this contractor licensed?" depends on where the house is.
This page is the standing reference for that difference. It does not restate current fee schedules, renewal cycles, or application requirements, because those change and we cannot verify them from here. It explains what regime each state runs and what that means you should ask for.
Three regimes, not ten
Some states issue a radon-specific licence through an environmental or emergency management agency. Illinois runs its programme through IEMA-OHS, and the licence is statewide — a licensed contractor from Rockford may work in Carbondale, which is why the county line is irrelevant to who may quote your house.
Some states certify through a health department or public health agency. Iowa, Minnesota, Ohio, and Kentucky each credential radon professionals through a state health authority; Pennsylvania certifies through its Department of Environmental Protection; Nebraska credentials through its health and human services department.
And some states do not credential radon work at the state level at all. Wisconsin, Michigan, and Colorado direct homeowners toward professionals certified through the national proficiency programmes — NRPP or NRSB. In those states the national certification is not a nice-to-have; it is the credential.
What changes for you between regimes
In a licensing state, verification is straightforward: ask for the number, confirm it is current, and confirm it covers mitigation rather than measurement alone. Those are two different credentials in every state that issues both, and a measurement credential does not authorise installing a system.
In a non-licensing state, there is no state register to check against, so the documentation carries more weight. Ask which national certification the contractor holds and confirm currency directly with the proficiency programme, and put more scrutiny on the written scope, the warranty terms, and whether a post-mitigation verification test is included.
The practical asymmetry is worth naming: an unlicensed state is not a state where standards are lower, but it is a state where nobody else is checking on your behalf.
- Ask for the credential number, not just the claim.
- Confirm it covers mitigation, not measurement only.
- Confirm it is current, not merely once-held.
- In non-licensing states, verify with NRPP or NRSB directly.
- Read the written scope and warranty with the same care either way.
What we do and do not verify
Radon Connect verifies a contractor’s credential with the issuing authority before any homeowner request routes to them, and re-checks currency on our own schedule. That is a claim about our intake process, and it is described in full at how we review contractors.
What we do not do is check a specific contractor for you on demand, and we do not warrant anyone’s work. The verification you perform yourself before signing is the one that protects you, and it takes a phone call.
Why this page avoids specifics that expire
Licensing details are exactly the kind of fact that goes stale quietly: fee schedules change, renewal cycles shift, agencies reorganise, and application requirements are amended without announcement. A page that restated all of that would be wrong within a year and would look authoritative while being wrong.
So each state resource centre names the agency that answers the question and tells you what to ask, rather than reproducing an answer we cannot re-verify. That is a deliberate accuracy trade, and it is why the state pages read as directories rather than encyclopaedias.
What would change this page
This is a standing reference rather than a report of a single event. Any of the following would require it to be revised, and the revision would be logged with a date:
- A state we serve introduces, removes, or restructures its radon credentialing regime.
- A state transfers its radon programme between agencies.
- NRPP or NRSB materially changes its certification categories.
Who licenses radon work: common questions
Is a contractor licensed in one state allowed to work in another?
Not automatically. Credentials are state instruments and do not travel across state lines by default. A contractor working in two states normally holds the credential each state requires — which is worth confirming directly in a metro that spans a state line.
Our state does not license radon work. Is that a problem?
It changes who is checking, not whether good contractors exist. In Wisconsin, Michigan, and Colorado the state health or radon programme directs homeowners toward NRPP or NRSB certified professionals, so confirm that certification is current and put more weight on the written scope and warranty.
What is the difference between a measurement and a mitigation credential?
Measurement covers testing; mitigation covers designing and installing systems. They are separate credentials in every state that issues both, and holding one does not authorise the other. Ask specifically which one a bidder holds.
How do we check a credential ourselves?
In a licensing state, contact the issuing agency named on that state’s resource centre. In a non-licensing state, contact NRPP or NRSB directly. Either way, verify the number rather than accepting a logo on a quote.
Where to go next
- State certification differences — Licensed states, certification states, and what to verify in each.
- NRPP certification — What the credential covers and how to verify it before hiring.
- NRSB certification — The second national credential — what it covers and how to check it.
- How to choose a radon contractor — The four-step screen: credential, diagnostic, written design, verified result.
States this bears on
- Illinois radon resources — Statewide IEMA-OHS licensing, a radon-specific disclosure statute, and how to verify both.
- Iowa radon resources — State health department certification, disclosure on the residential form, and consistently elevated results.
- Nebraska radon resources — State credentialing, radon-resistant new construction requirements, and negotiated remedies.
- Minnesota radon resources — A genuine state licence through MDH, plus a disclosure statute that acts before signing.
- Wisconsin radon resources — No state licence — national certification is the credential, and documentation carries more weight.
- Michigan radon resources — No state licence — verify national certification, and read the written scope harder.
- Ohio radon resources — A genuine state licence covering testers, contractors, and labs — and a disclosure form that asks directly.
- Pennsylvania radon resources — DEP certification is mandatory for radon services, and elevated results are common enough to expect.
- Colorado radon resources — No state licence, but a required warning statement before a sale — and a testing quirk worth knowing.
- Kentucky radon resources — State licensing through public health, plus karst geology that makes neighbourhood inference especially unreliable.
Related from the newsroom
- Licensing change mid-project — Open quote, scheduled install, or pending verification — how a regime change lands on each.
- If federal guidance changed — Which parts of a homeowner decision are anchored to the federal number, and which would not move at all.
The regime tells you where to check. It does not tell you whether a specific contractor is any good — that is what the written scope, the diagnostic, and the verification test are for.
Confidence and limits of this page
Every decision resource on this platform states its own boundaries. This is not a disclaimer — it is the part of this dispatch you should read before relying on it.
- What we knowClaims on this page we stand behind, each traceable to an approved source or to observable structure.
- Licensing of radon measurement and mitigation professionals is a state matter, and the ten states we cover do not hold a single common position.
- Illinois licenses both measurement and mitigation professionals under the statute cited here, and the state programme publishes a licensee list.
- What we do not knowQuestions you may reasonably have that this page does not answer.
- The present text of every state regulation described, since regimes change and this build environment cannot reach the publishing agencies to re-read them.
- Whether a given state list is current at the moment you read it, which only the issuing agency can confirm.
- What research would settle itWhat it would actually take to answer the above — naming it is the difference between honesty and hedging.
- A systematic re-read of each state statute and rule on a fixed schedule, which is the maintenance commitment our editorial standards describe and which requires network access to perform.
- A record of how often regimes change, which would let us set a review cadence from evidence rather than from judgement.
- What we do not claimClaims you might expect to find here and will not, with the reason.
- We do not give legal advice, and nothing here substitutes for counsel licensed in your state.
- We do not claim a regime is current as of today, only as of our stated review date, because a regime can change without our knowing.
- We do not claim any individual or business holds a credential; we tell readers to confirm it with the issuing authority.
- What we cannot independently verifyFacts this page relies on that we could not confirm ourselves.
- Whether a statute or rule we cite has been amended since our review date, for the network reason stated in our methodology.
- Any credential claim made by a business, which is exactly why we direct readers to the issuing authority instead.
Sources
- U.S. EPA — Radon
- IEMA-OHS — Illinois Emergency Management Agency and Office of Homeland Security — Radon Program
- Illinois General Assembly — Radon Industry Licensing Act (420 ILCS 44)
Get quotes from credentialed local contractors
Free to request, no obligation. We introduce homeowners to independent contractors whose credentials we verify with the issuing authority.