Professionals
Find a radon pro
Search by address, city, ZIP or state. Every listing shows the licenses on file, and you contact the business directly.
Updated October 2, 2026
Search
Find radon professionals for a home
Browse
Browse by state
Choose a state on the map or in the table. Each state's page explains its licensing rule and lists its cities.
- AK
- ME
- VT
- NH
- WA
- ID
- MT
- ND
- MN7
- IL387
- WI13
- MI6
- NY12
- RI
- MA2
- OR
- NV
- WY
- SD2
- IA210
- IN6
- OH6
- PA755
- NJ45
- CT2
- CA3
- UT
- CO
- NE12
- MO6
- KY12
- WV1
- VA4
- MD5
- DE25
- AZ
- NM
- KS
- AR
- TN1
- NC1
- SC7
- DC
- OK
- LA1
- MS
- AL2
- GA2
- HI
- TX3
- FL5
- PennsylvaniaListed: 755 · Testing: 657 · Mitigation: 136
- IllinoisListed: 373 · Testing: 287 · Mitigation: 94
- IowaListed: 203 · Testing: 150 · Mitigation: 91
| State | Listed | Testing | Mitigation |
|---|---|---|---|
| Pennsylvania | 755 | 657 | 136 |
| Illinois | 373 | 287 | 94 |
| Iowa | 203 | 150 | 91 |
Only states with listings of their own are in the table. Every state has its own page, with its licensing rule: choose it on the map or in the search above.
Short answer
Which professional do you need?
A radon specialist does one of three jobs. Start with your state's radon program, and look for NRPP or NRSB certification, the two national programs EPA names.
No result yet
A measurement professional
Tests the home's radon level under the conditions a reliable result needs, and reports it. Very often a home inspector.Testers (1,088)A high result
A mitigation contractor
Reviews your result, gives you a written proposal, then designs and installs a system to lower the level and makes sure it works.Mitigation companies (316)Behind every kit
A laboratory
Supplies test devices and analyzes them once they have been exposed in a home and sent back.Laboratories (35)
Radon411 lists 1,322 businesses today, read from the licensing lists Illinois, Iowa and Pennsylvania publish. A business that does both jobs counts in both.
Credentials
What certification and licensing mean
Two national programs certify individuals. A state licenses. They answer different questions.
- NRPP
- The National Radon Proficiency Program is recognized by EPA and accredited by the ANSI National Accreditation Board. Every certified individual must work to the applicable ANSI/AARST standards and document their competence every two years to stay certified.
- NRSB
- The National Radon Safety Board certifies Radon Measurement Technicians, Radon Measurement Specialists and Radon Mitigation Specialists, and accredits laboratories. Its certificate holders must follow the standards their state recognizes.
- A state license
- Licensing is done by the state, not by NRSB. EPA requires states that receive radon grants to give the public a list of only those providers credentialed by the state or by one of the two national programs, and many licensing states accept national certification toward their license.
What each state's own radon program says
EPA lists 20 states with radon credentialing programs to date. Each state's own program page is the rule to follow, and here is what each said when Radon411 read it.
14
Say they license or certify radon professionals
The state's own radon program page says the state licenses, certifies or registers people who test or mitigate.
California, Colorado, Florida, Illinois, Indiana, Iowa, Maine, Minnesota, Nebraska, New Jersey, Ohio, Pennsylvania, Rhode Island, West Virginia
9
Say they do not
The state's own page says it does not license or certify radon professionals. National certification is then the credential to ask for.
Connecticut, Georgia, Michigan, Montana, New Hampshire, New Mexico, New York, Texas, Wisconsin
2
Say something else
The page speaks to credentials without a yes or no: a rule that names the national programs, or a program still being written.
North Carolina, Virginia
The other 26 program pages (of 50 states and the District of Columbia) do not state a rule, or have not been read yet. Read from each state's own radon program page, checked on September 25, 2026. Each state's page here quotes its program's own sentence; choose yours on the map above or on the state radon programs page.
Before you hire
How to check a credential
A listing is not a credential. Check the professional against the body that issued theirs, in four steps.
Your state's own list
Start with your state's radon program. Licensing is done by the state, and most states can give you a list of radon service providers working there.NRPP's search
The National Radon Proficiency Program's search finds its Certified Mitigation Specialists and Certified Measurement Professionals by area, by name, or by the 6-digit NRPP ID number a professional can give you.NRSB's search
The National Radon Safety Board's search finds a professional in your area, or confirms that a named professional is NRSB certified.The ID card
The programs usually issue a photo ID card showing the holder's qualifications and its expiry date. Ask to see it, and if in doubt, check with the body that issued it.
In a state that does not regulate radon services, ask whether the professional holds a proficiency or certification credential and follows industry consensus standards, or has completed formal training in radon testing or mitigation.
Questions and warning signs
What to ask any radon company
Questions to ask
- Which credential do you hold, from whom, and what is the number? Can I see the ID card?
- Are you licensed, certified or registered where my state requires it?
- Will you give me references, and before and after test results from past radon work?
- Can you explain what the work involves, how long it takes and exactly how the system will work?
- Do you charge for diagnostic tests? Many contractors give free estimates but may charge for these.
- Do you guarantee to reduce radon to a level we agree, and for how long?
Warning signs
The same firm tests and fixes. That is a potential conflict of interest; EPA recommends that the test after mitigation be done by an independent, qualified tester.
No written proposal or contract. Ask for a contract before any work starts, and check that it matches the proposal.
A credential you cannot find. If the number is not in the issuing body's search or your state's list, ask why before you go further.
No test after the work. Test again after mitigation to confirm the level came down.
On cost: EPA says most homes can be fixed for about the same cost as other common home repairs, and to get an estimate from more than one qualified mitigator. The published figures are on what radon mitigation costs and what a radon test costs.
Trust
How these listings are verified
Listings come from the licensing lists Illinois, Iowa and Pennsylvania publish and from businesses that confirm their own details. Every card carries one label, and the label says exactly what was checked.
- Listed by state registry
This business appears on a state's published list of licensed radon professionals, which Radon411 read directly from the state's own site. The business has not confirmed these details itself.
- Claimed profile
The business confirmed these details itself. Radon411 has not independently checked them against an official record.
- Business information verified
Radon411 checked this business's details against an official record, such as a state contractor registry. This is a business status. It does not mean any specific certification has been verified, see each certification below for that.
- Certification verified
Radon411 retrieved this credential directly from the issuing body's own record and confirmed it matches this business.
- Not yet verified
The business, or a list it was imported from, reports this credential. Radon411 has not checked it against the issuing body's own record, so treat it as self-reported until it is.
- Unverified
This business's information was imported from a public source and has not yet been checked by Radon411 or confirmed by the business itself.
Three rules that never change
No one pays for a label. A label comes from where a listing was read or what was checked against the issuing body's own record. Approving a business's claim on its own listing can never mark a credential as verified.
No one pays for a place in the order. Lists are ordered by how much has been checked, then by name. A paid listing tier is not an input to the order at all.
No leads are sold. There is no quote form here. You contact a business directly, by its own website or phone number, and Radon411 never passes your details to anyone.
Run a radon business? Claim your listing to correct its details, or ask to be added.
Questions
Common questions
- What does NRPP certification mean?
NRPP is one of the two national radon proficiency programs EPA names. Its certified individuals must work to the applicable ANSI/AARST standards and document their competence every two years to keep the credential.
- What is an NRSB-certified radon specialist?
NRSB certifies measurement technicians and specialists and mitigation specialists. A mitigation specialist must be able to judge the quality of radon measurements, weigh alternative mitigation strategies, and design and install effective systems.
- Does my state license radon companies?
Each state's page here quotes its own radon program's rule, with the date it was read. See the states grouped by what their pages say.
- Is radon a problem in my area?
Only a test tells you about your own home. The radon map and each county's report show the area's predicted zone and measured results, and homes with elevated levels occur in all three zones.
- Who repairs an existing radon system?
A mitigation contractor. If the system's warning device shows it is not working properly, call a contractor to have it checked; fans may last five years or more and then need repair or replacement.
- Can a business pay to be listed higher or verified?
No. Labels come only from what was read or checked, and the order is by how much was checked, then by name. A paid tier is not an input to either.
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