Radon providers must be certified by the California Department of Public Health
Any person offering radon testing services, who is not a certified professional, is in violation of CA Health and Safety Code sec 106790. Any test results would be invalid for legal purposes. Violation of this regulation is considered a misdemeanor and the individual may be fined up to $1,000, and their business will be reported to the appropriate consumer protection agency or licensing board.
To verify that a person is a Certified Radon Tester click on this link: https://www.cdph.ca.gov/Programs/CEH/DRSEM/CDPH Document Library/EMB/Radon/Ca Cert Testers.pdf. To report a person selling radon services without the proper Certification, email the radon program at email@example.com or call (916) 449-5674.
California Civil Code Sec 1102 – 1102.18: Requires sellers of real property containing up to four residential units to complete a disclosure form indicating the presence of all environmental hazards, including radon gas, formaldehyde, and mold, that are known to the seller. Requires resale of manufactured homes and mobile homes to include disclosure of environmental hazards in the home interior or exterior, including radon, formaldehyde, and lead-based paint, as well as the existence of a carbon monoxide device.