Welcome to the State of California 

Certified Radon Services Providers

The Radon Program certifies all radon service providers operating in California. California law requires all radon professionals to be approved by either the National Radon Proficiency Program (NRPP) or National Radon Safety Board (NRSB).  There are no professional groups that are currently exempt from this requirement, including Home Inspectors, Industrial Hygienists, Registered Environmental Assessors (REAs), and Licensed Geologists. 

The California Department of Public Health does not endorse or recommend any company or individual over another.  As with any home service, you are advised to get more than one estimate.



Professional testers can provide test results faster than using a do-it-yourself test kit. Use a professional tester during a real estate transaction. They are also recommended for testing multi-family housing units, schools, non-residential buildings, and anytime you want quick results. The testers listed here have met their board requirements and are certified to operate in California:

Testers (PDF)


The mitigators listed below have met their board requirements and have met specific CA Contractors License requirements. They are certified to operate in California.

Mitigators (PDF)

A note about Contractors Licenses: Mitigators must also have a valid California Contractors License in one of a few specific categories. You can look up your contractor’s license here to make sure it meets our requirements.


The testers listed below have met their board requirements and are certified to operate in California:

Laboratories (PDF)


If someone offers you radon testing or mitigation and they are not on the approved lists here, they may NOT be certified to provide radon services in California.

To confirm a certification, report a problem, or report a business selling radon services without the proper Certification, email the radon program at radonprogram@cdph.ca.gov or call (916) 449-5674.

Last modified on: 10/28/2015 10:35 AM