Is Lawrence County, SD a radon risk area?

EPA's own radon map rates Lawrence County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Lawrence County sits at the 50th percentile nationally for radon potential — above 50 of every 100 rated counties.

How Lawrence County compares

About 28,809 people live in Lawrence County, South Dakota, spread over 800.053 square miles. That works out to roughly 36 people per square mile. Rank 497 by population within its EPA zone puts Lawrence County at the 52nd percentile among zone peers. Geologically, Lawrence County is grouped into EPA Region 8 alongside 290 other counties that share its rock and soil setting.

What this actually means for a house in Lawrence County

Lawrence County's predicted average falls between EPA's 4 pCi/L action level and the national indoor average of about 1.3 pCi/L (outdoor air runs roughly 0.4 pCi/L). Nothing about a Zone 2 label lowers the case for testing in Lawrence County — EPA recommends it in every zone, moderate included.

If Lawrence County tests above the action level

Nothing about Lawrence 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 South Dakota's state radon program

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

More on how this number was built

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