Is Mahaska County, IA a radon risk area?

Mahaska County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally that's the 83rd percentile for radon potential — Mahaska County outranks 83% of every county EPA has rated.

Where Mahaska County sits nationally

About 22,034 people live in Mahaska County, Iowa, spread over 570.851 square miles. That works out to roughly 39 people per square mile. Rank 541 by population within its EPA zone puts Mahaska County at the 49th percentile among zone peers. Geologically, Mahaska County is grouped into EPA Region 7 alongside 411 other counties that share its rock and soil setting.

Zone vs. an actual test

Where the national indoor average runs about 1.3 pCi/L, Mahaska 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 Mahaska 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.

Testing and mitigation in Mahaska County

Nothing about Mahaska 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 Iowa's state radon program

Mahaska County's test kit answers today; a Airthings radon monitor keeps answering for Mahaska 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. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.