Skip to content
RADON411

Radon professionals in California

Who tests and fixes radon in California, what California's own program says about licensing, and how to check a credential before you hire.

Updated October 2, 2026

Radon professionals listed for California

None that California licenses yet. The businesses below have an address here and another state licenses them.

No business licensed by California is listed here yet.

Located in California, licensed by another state

These businesses have an address in California, and another state's registry lists them. That does not mean California licenses them: check with California's radon program before hiring one for work here.

4 professionals located in California and listed by another state.

On this page: 2 testing and mitigation, 2 testing

Testing and mitigation 2

Testing 2

By city

3 cities in California with a listed business address.

Every radon business listed in California, A to Z (4)

Short answer

Radon professionals in California, in brief

No business that California itself licenses or certifies is listed on Radon411 yet. California's radon program says the state licenses or certifies radon professionals.

4 businesses with an address in California appear in a separate list because another state's registry lists them. That does not mean California licenses them.

The rule

Does California license radon professionals?

Yes. California's radon program page, checked on October 3, 2026, says:

The Radon Program certifies all radon service providers operating in California.
California Indoor Radon Program, read October 3, 2026

EPA's state contacts page lists California among the states with radon credentialing programs. Licensing is done by the state, not by the national programs, and EPA requires states that receive radon grants to give the public a list of only those providers credentialed by the state or by NRPP or NRSB.

The California Department of Public Health, Indoor Radon Program publishes its list of licensed radon professionals, last read on October 4, 2026. It names individual people, not businesses, and Radon411 lists businesses only, so no one on it is listed here. To check a person's license, use the state's own list.

State program

California's radon program

The state's own radon program: the place to ask who may work in the state.

California Indoor Radon Program

California Department of Public Health

Its page covers free or discounted test kits and who may test and fix radon in the state.

Phone 1-800-745-7236 · Email Radonprogram@cdph.ca.gov

Visit the program's page (opens in a new tab)Read October 3, 2026

Nearby

Listed professionals in states next to California

A business licensed in a neighboring state is licensed there, not necessarily in California. Check California's rule above before you hire one.

Before you hire

How to check a credential in California

  1. California's own list

    Start with the California Department of Public Health, Indoor Radon Program. Licensing is done by the state, so its list or search says who may legally work in California.

  2. 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.

  3. 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.

  4. 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.

Hiring

Hiring in California

A tester

Ask for the credential and ID card, how the test will be guarded against interference, and when the report will come. EPA recommends an independent, qualified tester for the test after a system is installed.

What a professional test involves

A mitigation contractor

Get more than one estimate, contact references, and ask for a written proposal and a contract before any work starts.

How to choose a contractor

Questions

Common questions about California

Does California require radon professionals to be licensed?

Yes. California's radon program page, checked on October 3, 2026, says.

EPA's state contacts page lists California among the states with radon credentialing programs.

The Radon Program certifies all radon service providers operating in California.
How do I find a certified radon mitigator in California?

No business is listed for mitigation in California on Radon411 yet.

Your state radon program can help you find qualified professionals in the state, and NRPP and NRSB, the two national proficiency programs EPA names, each publish a search of the professionals they certify.

How to choose a mitigation contractor

Who tests for radon in California?

No business is listed for radon measurement in California on Radon411 yet.

A qualified radon tester is very often a home inspector, and your state radon office can give you its approved list of radon testing companies.

What a professional radon test involves

Does California offer free or discounted radon test kits?

California Indoor Radon Program's page, checked on October 3, 2026, says:

Discounted test kits can be purchased through our partner laboratory, Alpha Energy, for $14.95.

Free and discounted test kits by state

How current are the California listings?

The California Department of Public Health, Indoor Radon Program publishes its list of licensed radon professionals, last read on October 4, 2026. It names individual people, not businesses, and Radon411 lists businesses only, so no one on it is listed here. To check a person's license, use the state's own list.

Is every business on this page licensed in California?

No listing here is a license. The first list holds businesses California's own registry lists, or that confirmed their own listing; each card names its source.

4 businesses with an address in California appear in a separate list because another state's registry lists them. That does not mean California licenses them.

How listings are verified. Run a radon business in California? Get Featured.

Next steps

Where to go next