What EPA's radon map says about Martin County

EPA's own radon map rates Martin County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. That puts Martin County in the 40th percentile nationally for radon potential — higher than 40% of the counties EPA has rated.

Where Martin County sits nationally

About 9,864 people live in Martin County, Indiana, spread over 335.761 square miles. That works out to roughly 29 people per square mile. Among counties sharing Martin County's EPA zone, it outranks 21% of them by population. Geologically, Martin County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

Zone vs. an actual test

Neither at the 4 pCi/L action level nor down at the roughly 1.3 pCi/L national indoor norm, Martin County's Zone 2 prediction lands in the gap between the two. Middle-of-the-pack doesn't mean risk-free for any one Martin County address — a moderate county average still leaves individual homes to test either side of it.

Testing and mitigation in Martin County

Mitigation cost doesn't depend on Martin 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

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

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.