What EPA's radon map says about Butler County

EPA's own radon map rates Butler County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Rank it against the rest of the country and Butler County lands in the 57th percentile for radon potential.

Butler County by the numbers

About 69,158 people live in Butler County, Kansas, spread over 1,429.716 square miles. That works out to roughly 48 people per square mile. Among counties sharing Butler County's EPA zone, it outranks 74% of them by population. EPA's geology-based Region 7 groups Butler County with 411 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

EPA's Zone 2 rating for Butler County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. Butler County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

If Butler County tests above the action level

Mitigation cost doesn't depend on Butler 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 Kansas's state radon program

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

The methodology guide shows exactly which EPA and Census sources feed Butler County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.