Published March 7, 2026
Radon Mitigation: What to Do After High Test Results
Rochester and Olmsted County are in a high-radon zone, with roughly 40% of homes testing above the EPA action level of 4.0 pCi/L. If your radon test returns elevated results, understanding your mitigation options helps you make informed decisions about protecting your family's health.
Understanding Your Results
Radon is measured in picocuries per liter (pCi/L). The EPA recommends action at 4.0 pCi/L or above, though some health organizations recommend mitigation at 2.0 pCi/L. There is no known safe level of radon exposure. In Rochester, we commonly see levels ranging from 2-12 pCi/L in unmitigated homes, with occasional readings above 20 pCi/L in homes with significant foundation issues.
How Mitigation Works
The most common and effective mitigation method is sub-slab depressurization (SSD). A pipe is inserted through the basement slab into the gravel layer beneath, and a fan creates negative pressure that draws radon gas from under the home and vents it above the roofline. This system typically reduces radon levels by 80-99% and costs $800-1,500 installed in Rochester. The fan runs continuously with minimal electricity cost ($50-75 per year).
Alternative Mitigation Approaches
Some Rochester homes require alternative or supplemental approaches. Crawl space homes may need sub-membrane depressurization. Homes with sump pits may route the mitigation system through the existing pit. Block wall suction addresses radon entry through hollow block foundations. Sealing major entry points (cracks, gaps around pipes, sump pit lids) supplements any mitigation system's effectiveness.
Post-Mitigation Testing
After mitigation installation, follow-up radon testing is essential to verify effectiveness. We recommend testing 24-48 hours after installation for initial verification, then long-term testing (90+ days) for accurate baseline measurement. Annual testing thereafter ensures the system continues to function properly. Our follow-up testing helps verify your mitigation investment is protecting your family.
Schedule Your Home Inspection Today
Trusted, thorough inspections for Rochester and SE Minnesota homebuyers.
Call (507) 721-0922