What EPA's radon map says about Buchanan County

EPA's own radon map rates Buchanan County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally that's the 82nd percentile for radon potential — Buchanan County outranks 82% of every county EPA has rated.

Where Buchanan County sits nationally

About 20,733 people live in Buchanan County, Iowa, spread over 571.084 square miles. That works out to roughly 36 people per square mile. Among counties sharing Buchanan County's EPA zone, it outranks 47% of them by population. Geologically, Buchanan County is grouped into EPA Region 7 alongside 411 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

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

Next steps for a home in Buchanan County

Mitigation cost doesn't depend on Buchanan 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

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

Buchanan 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.