Is Polk County, TN a radon risk area?

EPA places Polk County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Polk County sits at the 45th percentile nationally for radon potential — above 45 of every 100 rated counties.

Where Polk County sits nationally

About 18,338 people live in Polk County, Tennessee, spread over 434.605 square miles. Population density there runs about 42 people per square mile. Rank 655 by population within its EPA zone puts Polk County at the 37th percentile among zone peers. Geologically, Polk County is grouped into EPA Region 4 alongside 735 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

Neither at the 4 pCi/L action level nor down at the roughly 1.3 pCi/L national indoor norm, Polk County's Zone 2 prediction lands in the gap between the two. Nothing about a Zone 2 label lowers the case for testing in Polk County — EPA recommends it in every zone, moderate included.

Next steps for a home in Polk County

Nothing about Polk 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 Tennessee's state radon program

Polk County's test kit answers today; a Airthings radon monitor keeps answering for Polk 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 Polk County's numbers. Whatever zone Polk County carries, the zone explainer covers what it does and doesn't tell you about any one house.