February 19, 2026 · By Master Certified InterNACHI Member, Master Certified Professional Inspector (CPI)
Radon in Scott County MN: Why EPA Zone 1 Changes Everything
Radon is the single highest-volume add-on request on a Shakopee MN home inspection — and for good reason. Scott County is EPA Radon Zone 1, the highest-risk classification the EPA assigns, and roughly 2 in 5 Minnesota homes tested exceed the EPA action level of 4.0 pCi/L. We include continuous-monitor radon testing alongside any inspection. See radon testing details on our services page, browse our Shakopee home inspection services, or get an instant quote.
What is EPA Zone 1?
The EPA classifies every US county into one of three radon zones based on predicted indoor-air radon levels. Zone 1 means the predicted average screening level is greater than 4.0 pCi/L — the EPA action level. Zone 1 includes all of Scott County: Shakopee, Prior Lake, Savage, and Jordan.
Why Minnesota has a radon problem
The short answer is geology. Minnesota sits on glacial till rich in uranium, and our homes are heated 8+ months of the year — which means they’re closed up and pressurized differently than homes in warmer climates. Combined, those factors produce some of the highest indoor radon levels in the country.
The Minnesota Department of Health reports that more than 2 in 5 homes tested statewide exceed the EPA action level. In Scott County specifically, the percentage is higher still.
What the numbers mean
- Below 2.0 pCi/L — low. Retest every 2–5 years.
- 2.0–4.0 pCi/L — moderate. Consider mitigation.
- 4.0 pCi/L and above — EPA action level. Mitigate.
- 10 pCi/L and above — aggressive mitigation and ventilation improvements.
How to test
Two options:
- DIY charcoal kit ($10–$15 from MDH). Good for baseline screening. You expose it for 48–96 hours, mail it to the lab, get results in 1–2 weeks.
- Professional continuous-monitor test ($150–$200). A calibrated electronic device records hourly. Best for real estate transactions — can’t be tampered with and produces an hour-by-hour chart.
If you test high
Install an active sub-slab depressurization (ASD) system. A fan and a PVC pipe pull soil gas from beneath the basement slab and vent it above the roof. Installed by a licensed Minnesota mitigator, a standard ASD system costs $1,200–$2,500 and routinely brings indoor levels below 1 pCi/L.
Always retest after mitigation — and again every 2 years to verify the system is still performing.
What this means for buyers
- Radon test every home you’re about to buy. Every time.
- If the home already has a mitigation system, verify it’s working with a fresh test. Systems fail when fans die or pipes get disconnected during renovations.
- Write radon testing into your purchase agreement with a 4.0 pCi/L mitigation trigger.
What this means for sellers
- Test before listing. A clean radon report is a marketing asset.
- If you test high, mitigate before listing. Buyers will insist; doing it on your timeline costs less than doing it under a closing deadline.
- Keep mitigation receipts and post-mitigation test results — they’re disclosure-protective.