California
What is the testing mandated for California?
For California, testing mandated is No; professional certification required is Yes; no person may provide radon services for the general public unless that person has completed the National Radon Measurement Proficiency Program of the National Environmental Health Association or the National Radon Safety Board Certified Radon Professional Program; action level pci l is No state-specific action level; follows EPA recommended 4 pCi/L; school testing required is No; statute citation is California Civil Code §§ 1102--1102.18; California Health & Safety Code §§ 106750 et seq, recorded from its source on 2026-08-15; source re-checked 2026-10-01.
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
— eli.org, retrieved 2026-08-15
- jurisdiction
- California
- disclosure required
- Yes; part of a general environmental hazard disclosure form. Sellers of up to four residential units must disclose the presence of environmental hazards including radon gas.
- testing mandated
- No
- professional certification required
- Yes; no person may provide radon services for the general public unless that person has completed the National Radon Measurement Proficiency Program of the National Environmental Health Association or the National Radon Safety Board Certified Radon Professional Program
- action level pci l
- No state-specific action level; follows EPA recommended 4 pCi/L
- school testing required
- No
- statute citation
- California Civil Code §§ 1102--1102.18; California Health & Safety Code §§ 106750 et seq.
Source
- eli.orghttps://www.eli.org/sites/default/files/files-pdf/2025%20Radon.pdf