Best Radon Testing in Los Angeles, CA

How much does radon testing cost in California?

Professional radon testing typically costs $175 to $350. Short-term tests (48-96 hours) are used for real estate transactions. Long-term tests (90+ days) provide the most accurate annual average. **CDPH** recommends professional testing over DIY kits for real estate transactions, though DIY kits ($20-$40) are available at hardware stores.

Why is radon especially concerning in California?

California has varying radon levels depending on geology. **Granitic foothill counties and other radon-prone geologic zones** have elevated radon risk due to bedrock composition. Even other areas of the state have measurable radon. **CDPH** considers it a public health issue and publishes county-level radon data.

Are radon testers required to be certified in California?

California does not maintain a single statewide radon tester license like some trades. **CDPH** and professional organizations like the National Radon Proficiency Program (NRPP) or National Radon Safety Board (NRSB) recommend certified testers. For real estate transactions, use a certified professional to ensure legally defensible results.

What happens if my California home has high radon levels?

If radon levels exceed 4 pCi/L, the EPA and **CDPH** recommend installing a radon mitigation system. Sub-slab depressurization is the most effective method and typically costs $1,000 to $2,000. NRPP- or NRSB-certified mitigation contractors can perform installation. Mitigation reduces levels by up to 99%.

When should I test for radon in my California home?

**CDPH** recommends testing all homes, especially in high-risk areas. Test when buying or selling, after major renovations affecting the foundation, or if you have never tested. Testing during cooler months (November through March) with windows closed provides the most representative results. Re-test every 2 years or after major changes to the home.