Radon Mitigation Services for Homes and Buildings
Radon is a naturally occurring radioactive gas that forms from the decay of uranium in soil and rock. It is colorless, odorless, and tasteless — impossible to detect without testing. When radon seeps into a home through foundation cracks, construction joints, or gaps around service pipes, it can accumulate to levels the EPA classifies as a health concern. The EPA estimates that radon causes approximately 21,000 lung cancer deaths in the United States each year, making it the second leading cause of lung cancer after smoking. Radon mitigation is the proven, permanent solution to elevated indoor radon levels. A professionally installed system reduces radon concentrations to safe levels and protects every occupant in the building.
How Radon Mitigation Works
The most effective and widely used radon mitigation method is sub-slab depressurization (SSD). This technique creates a pressure differential beneath the foundation slab, drawing radon gas away from the living space before it can enter. A certified contractor drills one or more suction points through the concrete floor, installs a PVC pipe, and connects a continuously running fan. The fan creates negative pressure below the slab, capturing radon at its source and venting it outside through a pipe that exits above the roofline or through the side of the home.
For homes with crawl spaces, a sub-membrane depressurization system is installed instead. A durable plastic membrane covers the crawl space floor, and a fan draws radon from beneath it. Block wall depressurization is available for homes with hollow concrete block foundations. In all cases, the goal is the same: intercept radon before it enters living areas and vent it safely to the exterior.
Systems are designed to run continuously with minimal energy use. Most residential radon fans consume between 20 and 90 watts — comparable to a standard light bulb. Properly sized systems operate quietly and require little ongoing maintenance beyond an annual inspection.
What to Expect During a Radon Mitigation Installation
A standard residential installation follows a consistent process. Before the appointment, the contractor reviews the home’s foundation type, reviews any existing radon test results, and selects the appropriate system design. On installation day, the process typically takes 3 to 5 hours for a single-system home.
- Site assessment: The technician inspects the foundation, identifies suction point locations, and determines the optimal pipe routing.
- Suction point installation: One or more holes are drilled through the concrete slab at strategic locations. Diagnostic testing confirms adequate pressure field extension.
- Pipe and fan installation: PVC pipe is routed from the suction point through the home (interior) or along the exterior wall to above the roofline. The radon fan is mounted and connected.
- Sealing: Visible cracks and openings in the slab are sealed with polyurethane caulk to improve system performance.
- System labeling: The fan, pipe, and electrical connection are labeled per state and AARST-NRPP standards for future reference.
- Post-installation briefing: The technician explains system operation, warning devices, and the recommended post-mitigation test timeline.
Post-mitigation testing is strongly recommended 24 to 48 hours after installation to confirm the system is performing correctly. Many states require post-mitigation testing as a condition of contractor certification. See our radon testing services for information on test kits and professional testing options.
Radon Levels and EPA Action Thresholds
The EPA uses picocuries per liter (pCi/L) to measure radon concentration. The national average indoor radon level is approximately 1.3 pCi/L. The EPA recommends mitigation when levels reach 4 pCi/L or higher, and considers action at levels between 2 and 4 pCi/L. The World Health Organization (WHO) recommends a lower reference level of 2.7 pCi/L (100 Bq/m³) where feasible.
| Radon Level | Risk Category | Recommended Action |
|---|---|---|
| Below 2 pCi/L | Low | No action required; retest every 2 years |
| 2–4 pCi/L | Moderate | Consider mitigation; WHO advises action |
| 4 pCi/L or higher | Elevated | EPA recommends mitigation |
| 8 pCi/L or higher | High | Mitigate within 3 months |
| 20 pCi/L or higher | Very High | Mitigate as soon as possible |
Radon levels vary significantly by region. The EPA’s Map of Radon Zones identifies high-risk areas across the country, including large portions of the Midwest, Mountain West, and mid-Atlantic states. Even homes in lower-risk zones can have elevated radon — every home should be tested regardless of location or age.
Frequently Asked Questions About Radon Mitigation
What is radon mitigation?
Radon mitigation is the process of reducing radon gas concentrations inside a building to safe levels. The most common method is sub-slab depressurization (SSD), which uses a continuously running fan and pipe system to draw radon from beneath the foundation and vent it safely outside. A properly installed system can reduce indoor radon by up to 99%.
What radon level requires mitigation?
The EPA recommends mitigation when indoor radon levels are at or above 4 pCi/L. The EPA also suggests considering mitigation for levels between 2 and 4 pCi/L. The WHO sets its reference level at 2.7 pCi/L. There is no radon level that is completely without risk — lower is always better.
How long does radon mitigation take?
Most residential installations are completed in 3 to 5 hours in a single day. The system begins reducing radon levels immediately upon activation. A post-mitigation test is recommended 24 to 48 hours after installation to verify that radon levels have dropped below the EPA action level.
Does radon mitigation work?
Yes. Sub-slab depressurization systems are highly effective and endorsed by the EPA and AARST-NRPP as the industry standard. When correctly designed and installed, these systems reduce indoor radon levels by up to 99% in most homes. System effectiveness should be verified with a post-mitigation test and confirmed with periodic retesting every 2 years.
How much does radon mitigation cost?
Residential radon mitigation typically costs between $800 and $2,500, depending on foundation type, home size, radon levels, and local labor rates. Most single-family homes require one system installation. Homes with complex foundations, multiple foundation types, or very high radon levels may require additional suction points or fans. Request a site assessment for an accurate quote.
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