Radon Mitigation Pros in San Francisco, CA

Finding a qualified radon mitigation contractor in San Francisco shouldn’t feel like navigating a permit maze blindfolded, but for most homeowners it does — the market is thin, certifications vary wildly, and half the companies that show up in search results are HVAC generalists who added “radon” to their website last year. This directory cuts through that. Every contractor listed here holds active NRPP or NRSB certification, which means they’ve passed third-party proficiency exams — not just watched a YouTube series.

How to Choose a Radon Mitigation Contractor in San Francisco

• Verify the credential, not just the claim. Ask for the contractor’s NRPP or NRSB certificate number and confirm it’s current at nrpp.info or nrsb.org. California doesn’t license radon contractors at the state level, so national certification is the only meaningful vetting mechanism you have.
• Separate measurement from mitigation. These are distinct credentials. If you need testing and a mitigation system, confirm the contractor holds (or partners with someone who holds) both a Certified Radon Measurement Professional credential and a Certified Radon Mitigation Specialist credential — one firm doing both isn’t a conflict of interest, but you want both boxes checked.
• Ask about post-mitigation testing protocol. Any reputable contractor will include a short-term test (48–96 hours) after installation to confirm the system is working. If they don’t offer it or quote it as an add-on, that’s a red flag.
• Get the warranty in writing. Good systems come with a workmanship warranty of at least one year and a guarantee that radon levels will drop below 4 pCi/L. If a contractor won’t put a performance guarantee in writing, keep looking.
• Check for permit experience in San Francisco. SF’s Department of Building Inspection requires permits for sub-slab depressurization work in most cases. Contractors unfamiliar with DBI’s process can create delays that cost you a real estate transaction.

Pro Tip: If you’re in a real estate transaction, ask your contractor how many SF closings they’ve supported. The DBI permit turnaround and the tight timelines of a contingency window require someone who knows the city’s process — not a contractor who’s never pulled a permit in SF County.

What to Expect

Testing alone runs $150–$400 depending on the number of tests and whether you need a professional report for a real estate disclosure packet. Full active soil depressurization (ASD) system installation — the standard fix for elevated levels — runs $800–$1,500 for most single-family homes and ground-floor condos in San Francisco, with the variance driven by slab type, crawl space complexity, and access to an exterior roofline vent path. Most installs are completed in a single day, with post-mitigation test results back within 3–5 days.

Reality Check: The cheapest quote is almost never the cheapest outcome. Contractors who underbid often skip the post-mitigation test, install undersized fans, or route the vent in a way that fails DBI inspection — leaving you to pay someone else to fix it. Get three quotes, compare the scope of work line by line, and weight the post-mitigation guarantee heavily.

Local Market Overview

San Francisco sits primarily in EPA Radon Zone 2 (moderate potential, 2–4 pCi/L predicted average), but local geology — particularly in neighborhoods underlain by serpentinite and older bay fill — creates meaningful variability that makes city-wide assumptions unreliable. California’s real estate disclosure laws require sellers to provide buyers with the EPA’s radon guide, and lenders on FHA/VA loans increasingly require documented mitigation when test results exceed 4 pCi/L, which means radon contractors here are often working against escrow deadlines — another reason to hire someone who knows this market specifically.