Maryland Radon Mitigation: Certification, Permits, and What to Do

Contractor Certification in Maryland

MDE-certified contractors must follow AARST ANSI installation standards. The Piedmont and Appalachian regions of Maryland have the highest radon geology risk. Montgomery and Frederick counties have significant Zone 1 areas.

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

Maryland 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 Maryland

Maryland has counties in EPA Radon Zone 1 & 2. 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 Maryland 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 Maryland-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 Maryland: $900–$2,100.
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