What EPA's radon map says about Iowa County

EPA's own radon map rates Iowa County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. That puts Iowa County in the 83rd percentile nationally for radon potential — higher than 83% of the counties EPA has rated.

Iowa County by the numbers

About 23,963 people live in Iowa County, Wisconsin, spread over 762.698 square miles. That works out to roughly 31 people per square mile. Among counties sharing Iowa County's EPA zone, it outranks 51% of them by population. Iowa County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Where the national indoor average runs about 1.3 pCi/L, Iowa County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Iowa County will test well under the action level, and EPA's guidance is to test regardless of zone.

Testing and mitigation in Iowa County

Mitigation cost doesn't depend on Iowa 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

Iowa County's test kit answers today; a Airthings radon monitor keeps answering for Iowa 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

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.