What EPA's radon map says about Polk County

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 54th percentile nationally for radon potential — above 54 of every 100 rated counties.

How Polk County compares

About 45,831 people live in Polk County, Wisconsin, spread over 914.319 square miles. Averaged across its land area, Polk County runs about 50 people per square mile. Among counties sharing Polk County's EPA zone, it outranks 65% of them by population. Geologically, Polk County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

What this actually means for a house in Polk County

EPA's Zone 2 rating for Polk County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. A county-wide moderate average, like Polk County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Testing and mitigation in Polk County

Mitigation cost doesn't depend on Polk County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find Wisconsin'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

Polk County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.