Radon Mitigation Pros in Fresno, CA

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Most homeowners searching for a radon mitigation contractor in Fresno hit the same wall: a handful of HVAC generalists who “do radon too,” no obvious way to verify credentials, and quotes that vary by $600 with no explanation for the difference. This directory cuts through that by listing only verified, certified contractors — so you’re not playing roulette with your indoor air.

How to Choose a Radon Mitigation Contractor in Fresno

• Demand proof of NRPP or NRSB certification — separately for testing and mitigation. These are different credentials. A contractor certified only in measurement cannot legally or ethically sign off on a mitigation installation. Ask for both cert numbers and verify them at nrpp.info or nrsb.org before you schedule anything.
• Ask if they pull a building permit. California doesn’t have a statewide radon contractor licensing law, which means anyone with a van can call themselves a radon company. Pulling a permit for the ASD (active soil depressurization) installation signals the contractor is operating above the minimum bar.
• Get a post-mitigation test in writing. Any legitimate contractor will include a follow-up measurement — or clearly price it separately — to confirm the system drove levels below 4 pCi/L. If they don’t mention it, that’s your cue to move on.
• Check whether they’re testing and mitigating. Some contractors do both; others subcontract the measurement piece. Either model is fine, but you want to know who’s accountable for what — and who signs the final report.
• Fresno’s older housing stock matters. Much of central Fresno was built on flat valley fill with slab-on-grade construction — a foundation type that responds well to ASD, but only when the contractor properly diagnoses sub-slab communication before drilling. Ask them how they assess this before quoting.

Pro Tip: The EPA’s map puts most of Fresno County in Zone 2 (moderate potential), but that’s a county-level average. Neighborhoods closer to the Sierra Nevada foothills — Clovis, northeast Fresno — can test significantly higher. Don’t assume Zone 2 means you’re safe; test first.

What to Expect

Testing runs $150–$400 depending on whether you use a short-term charcoal kit (lab-analyzed) or hire a pro with a continuous monitor that logs hourly readings — the latter is worth it for real-estate transactions where you need a defensible report fast. If levels come back above 4 pCi/L, mitigation installs typically run $800–$1,500 for a standard single-entry-point ASD system; multi-point systems or complex crawlspaces push toward the top of that range.

Reality Check: If a contractor quotes you $400 for “full mitigation,” they’re either cutting corners on the fan, skipping the post-test, or both. The fan alone — a quality Festa or RadonAway unit — costs $150–$250 wholesale. The math doesn’t work at that price point, and you’ll find out the hard way when your follow-up test still reads 6 pCi/L.

Local Market Overview

Fresno’s active real-estate market — consistently one of California’s highest-volume transaction cities — means radon testing demand spikes hard during escrow season, and contractors who primarily serve the Clovis and northeast Fresno markets book out quickly in spring. If you’re on a 10-day inspection contingency, call the day you open escrow, not the day before your deadline.