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 51st percentile nationally for radon potential — above 51 of every 100 rated counties.

Polk County by the numbers

About 33,070 people live in Polk County, Missouri, spread over 635.527 square miles. That works out to roughly 52 people per square mile. Among counties sharing Polk County's EPA zone, it outranks 55% of them by population. EPA's geology-based Region 7 groups Polk County with 411 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Call it a middle case: above the 1.3 pCi/L most US homes average, below the 4 pCi/L line EPA uses to recommend mitigation — that's Polk County's Zone 2 prediction. A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in Polk County — testing is the only way to know an individual home's actual level.

Next steps for a home 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 Missouri'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. RADONZONE-10OFF at checkout knocks 10% off.

More on how this number was built

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Polk County carries, the zone explainer covers what it does and doesn't tell you about any one house.