Montana Radon Mitigation: What Homeowners Need to Know

Contractor Certification in Montana

Because Montana has no mandatory contractor certification, homeowners must rely on national NRPP or NRSB credentials to vet professionals. Montana DEQ recommends testing homes in Zone 1 and Zone 2 counties and retesting every two years if levels were previously low.

Regardless of state licensing requirements, always verify that any radon contractor you hire holds current NRPP certification (nrpp.info) or NRSB certification (nrsb.org). These national certifications require passing a written exam and adhering to AARST ANSI installation standards.

Permit Requirements

Montana does not require a statewide building permit for radon mitigation in existing single-family homes. An electrical permit is typically required at the local level when a new circuit or outlet is installed for the radon fan. Confirm with your local building department before work begins.

Radon Zones in Montana

Montana has counties in EPA Radon Zone 2 & 3. Zone 1 counties have the highest predicted average indoor radon levels. Even homes in lower-zone counties can test high — the only way to know your home's actual level is to test it with a certified test device.

What Montana Homeowners Should Do

1. Confirm your test result. At or above 4 pCi/L on a confirmed long-term test, proceed with mitigation. At 8+ pCi/L, act without further delay.
2. Find 2–3 certified contractors. Search NRPP at nrpp.info or NRSB at nrsb.org for Montana-based certified mitigators. Get written quotes.
3. Confirm permit requirements. Ask your contractor: "Will you pull an electrical permit if new wiring is needed?" Confirm with your local building department.
4. Schedule installation. Standard SSD installation takes 3–8 hours. Typical cost in Montana: $800–$1,800.
5. Post-mitigation test. Wait 24–48 hours after installation, then run a radon test. Target: below 4 pCi/L, ideally below 2 pCi/L.

Frequently Asked Questions