Is Hamilton County, IA a radon risk area?

EPA's own radon map rates Hamilton County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally, Hamilton County ranks higher in radon potential than 79% of rated counties (the 79th percentile).

Where Hamilton County sits nationally

About 14,856 people live in Hamilton County, Iowa, spread over 576.731 square miles. Population density there runs about 26 people per square mile. Rank 662 by population within its EPA zone puts Hamilton County at the 38th percentile among zone peers. Geologically, Hamilton 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, Hamilton County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. Some Hamilton County homes will test comfortably under the action level despite the county's Zone 1 rating — the only way to know which kind of home you have is an actual test.

Testing and mitigation in Hamilton County

Nothing about Hamilton 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

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

Hamilton County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.