What EPA's radon map says about Randolph County

EPA's own radon map rates Randolph County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Nationally that's the 48th percentile for radon potential — Randolph County outranks 48% of every county EPA has rated.

How Randolph County compares

About 24,077 people live in Randolph County, Missouri, spread over 482.713 square miles. That works out to roughly 50 people per square mile. Among counties sharing Randolph County's EPA zone, it outranks 45% of them by population. Randolph County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

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, Randolph County's Zone 2 prediction lands in the gap between the two. A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in Randolph County — testing is the only way to know an individual home's actual level.

Testing and mitigation in Randolph County

Mitigation cost doesn't depend on Randolph 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 Missouri's state radon program

Randolph County's test kit answers today; a Airthings radon monitor keeps answering for Randolph 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 Randolph County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.