Radon in Hennepin County: What 4.0 pCi/L Means for Your Basement

Radon is a colorless, odorless radioactive gas and the leading cause of lung cancer in non-smokers. The Minnesota Department of Health reports that a large share of Hennepin County homes test above the EPA action level of 4.0 pCi/L — and in Minnetonka, walkout basements on the lake are a common pathway for it.

Why walkout basements test high

Radon enters through the soil contact a home has with the ground. Walkout and lookout basements — extremely common on Minnetonka's sloped lake-adjacent lots — have extensive below-grade contact and often finished living space right where the gas accumulates.

That combination of geology and floor plan is why we treat radon testing as standard on walkout homes here, not optional.

How testing works and what to do

An EPA-protocol continuous monitor runs a minimum of 48 hours under closed-house conditions, producing an hour-by-hour record rather than a single number. At or above 4.0 pCi/L, the EPA recommends mitigation — a sub-slab depressurization system that is straightforward and effective.

If you are buying a walkout on Excelsior Bay or anywhere along the lake, pair radon with your home inspection. See our radon measurement service for details.

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