Is Watonwan County, MN a radon risk area?

Watonwan County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Watonwan County sits at the 76th percentile nationally for radon potential — above 76 of every 100 rated counties.

Watonwan County by the numbers

About 11,204 people live in Watonwan County, Minnesota, spread over 434.947 square miles. Population density there runs about 26 people per square mile. Rank 739 by population within its EPA zone puts Watonwan County at the 31st percentile among zone peers. Geologically, Watonwan County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

Watonwan County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Watonwan County will test well under the action level, and EPA's guidance is to test regardless of zone.

Testing and mitigation in Watonwan County

Nothing about Watonwan County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find Minnesota's state radon program

Watonwan County's test kit answers today; a Airthings radon monitor keeps answering for Watonwan County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed Watonwan County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.