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License check

How to check a radon contractor's license

All four states we cover require a state credential to test for radon or install a mitigation system. Checking one is quick: get the person's name and license number, look it up on the state's own list, and make sure the license type matches the job. Every RadonScout listing shows the credential numbers we found on the state roster and that roster's date, so you can start there.

1. Ask for the number
A credentialed tester or installer will give you their state license or certification number. Ask for the individual's number, not just the company name.
2. Look it up on the state's list
Use the official lookup for your state below, not a number on the contractor's own website.
3. Match the license to the job
Testing and mitigation are separate credentials in every state here. Someone licensed only to test can't install your system.

Iowa

Iowa HHS · Iowa listings →

Testers are certified measurement specialists (numbers start RNTST); installers are credentialed mitigation specialists (numbers start RNMIT).

  1. Open Iowa HHS's current lists: mitigation specialists (PDF) and measurement specialists (PDF). Each shows the report date at the top.
  2. Search the PDF (Ctrl+F) for the person's or company's name and confirm the number they gave you.
  3. Match the type to the job: a mitigation system needs an RNMIT credential; a test needs RNTST.
  4. The lists don't show expiration dates. If someone isn't on the latest list, call the Iowa Radon Hotline at 1-800-383-5992 before hiring.
Source: Iowa HHS mitigation specialists list (report dated 9/24/2026); Iowa HHS radon credentialing. Checked 2026-11-05.

Nebraska

Nebraska DHHS · Nebraska listings →

Nebraska licenses both individuals (measurement or mitigation specialists) and businesses; business license numbers look like RMB- (measurement) and RCB- (mitigation) on DHHS reports.

  1. Go to the state's free License Lookup.
  2. Search the person's or company's name and check that the license is active and is the right type (measurement or mitigation).
  3. DHHS also posts business reports: mitigation businesses (PDF) and measurement businesses (PDF).
  4. Questions: Nebraska radon program 402-471-0386.
Source: Nebraska DHHS radon licensing. Checked 2026-11-05.

Colorado

Colorado DORA · Colorado listings →

Colorado licenses radon measurement professionals (numbers start RME-) and mitigation professionals (RMT-). A license has been required since July 1, 2022.

  1. Open DORA's license lookup.
  2. Search by the person's name or license number.
  3. Check that the status is active and that the license type fits the job (RMT for a system, RME for a test).
  4. Questions or complaints: DORA radon program, dora_radon@state.co.us or 303-894-7800.
Source: DORA Office of Radon Professionals; DORA press release, Aug. 16, 2022. Checked 2026-11-05.

Kansas

KDHE · Kansas listings →

Kansas certifies measurement technicians (KS-MS-) and mitigation technicians (KS-MI-). Certification lasts two years.

  1. Use KDHE's certified radon professionals map (search an address, then filter to measurement or mitigation), or the full list (PDF).
  2. Find the technician's name and confirm the certification number they gave you.
  3. Match the type to the job: KS-MI for a mitigation system, KS-MS for a test. Watch for entries marked terminated.
  4. Ask to see a current certificate if anything doesn't match. Questions: Kansas Radon Program 785-296-1560.
Source: KDHE Radon Professionals; KDHE certified technicians list (dated 2026-04-13). Checked 2026-11-05.

National certification (NRPP and NRSB)

Many professionals also hold a national certification from the National Radon Proficiency Program (NRPP search) or the National Radon Safety Board (NRSB search). Both are EPA-recognized and require training, an exam and continuing education. In these four states the state credential is the legal requirement, so check that first and treat national certification as an extra signal.

Source: Wisconsin DHS, Radon: How to Find a Contractor (describes both programs). Checked 2026-11-05.

Related

Got a test result back? What your number means. What each state requires beyond licensing: radon laws by state. What a fix should cost and the questions to ask every installer: radon mitigation cost guide.