What EPA's radon map says about Boone County

EPA's own radon map rates Boone County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. That puts Boone County in the 93rd percentile nationally for radon potential — higher than 93% of the counties EPA has rated.

Boone County by the numbers

About 78,773 people live in Boone County, Indiana, spread over 422.882 square miles. That works out to roughly 186 people per square mile. Among counties sharing Boone County's EPA zone, it outranks 79% of them by population. Boone County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

Why the zone isn't the answer by itself

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Boone County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. EPA's guidance doesn't change because of a Zone 1 label: test the house. What changes is the reason to not put it off in Boone County specifically.

Testing and mitigation in Boone County

Mitigation cost doesn't depend on Boone 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 Indiana's state radon program

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

Boone 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.