What EPA's radon map says about Osceola County

EPA's own radon map rates Osceola County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Osceola County sits at the 72nd percentile nationally for radon potential — above 72 of every 100 rated counties.

Osceola County by the numbers

About 6,036 people live in Osceola County, Iowa, spread over 398.687 square miles. Averaged across its land area, Osceola County runs about 15 people per square mile. Among counties sharing Osceola County's EPA zone, it outranks 17% of them by population. EPA's geology-based Region 7 groups Osceola County with 411 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Where the national indoor average runs about 1.3 pCi/L, Osceola County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. Being in Zone 1 raises the odds Osceola County homes test above the action level, but it does not mean any specific house does — EPA recommends every home be tested, in every zone, because the only way to know is to test.

If Osceola County tests above the action level

Mitigation cost doesn't depend on Osceola 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 Iowa's state radon program

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

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 Osceola County carries, the zone explainer covers what it does and doesn't tell you about any one house.