Radon Risk Calculator
Check your ZIP code's EPA radon zone, estimated indoor levels, and get mitigation guidance with cost estimates.
- EPA radon zone (1-3) with predicted indoor levels in pCi/L
- Risk assessment adjusted for foundation type and home age
- Testing options comparison and mitigation cost estimates
How This Calculator Works
- Enter your ZIP code — we look up the EPA radon zone classification (Zone 1 = highest risk, Zone 3 = lowest).
- Specify your foundation type — basements have the highest radon entry potential.
- Get your risk assessment — estimated indoor radon level, testing recommendations, and mitigation options with costs.
EPA Radon Zones Explained
| Zone | Predicted Avg. Level | Risk | EPA Recommendation |
|---|---|---|---|
| Zone 1 (High) | Above 4 pCi/L | Highest priority | Test all homes; mitigate if above 4 pCi/L |
| Zone 2 (Moderate) | 2 - 4 pCi/L | Moderate | Test all homes; consider mitigation above 2 pCi/L |
| Zone 3 (Low) | Below 2 pCi/L | Lower priority | Test recommended; mitigation if above 4 pCi/L |
Why Radon Matters
Radon is a naturally occurring radioactive gas that comes from the decay of uranium in soil and rock. It enters homes through cracks in foundations, gaps around pipes, and other openings. The EPA and Surgeon General recommend testing all homes below the third floor.
The EPA action level is 4 pCi/L, but the WHO recommends considering mitigation at 2.7 pCi/L. There is no known safe level of radon exposure.
Order a radon test kit or find a certified tester in your area.
Find a Certified Radon TesterThe EPA maintains a list of certified radon measurement and mitigation professionals.
Data Sources & Methodology
Data Sources
- EPA Map of Radon Zones — County-level radon zone classification (Zone 1-3) for all U.S. counties
- U.S. Census ACS — Median home age and housing characteristics by ZIP code
- State Radon Programs & AARST — Mitigation cost data and professional standards
Methodology
We map your ZIP code to its EPA radon zone, then adjust estimated indoor levels based on foundation type (basement = 1.3x, slab = 0.8x) and home age (40+ years = 1.2x multiplier for additional entry points). Cost estimates reflect typical sub-slab depressurization system installations.