What EPA's radon map says about Clark County

Clark County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. That puts Clark County in the 14th percentile nationally for radon potential — higher than 14% of the counties EPA has rated.

Where Clark County sits nationally

About 20,920 people live in Clark County, Arkansas, spread over 865.971 square miles. Population density there runs about 24 people per square mile. Among counties sharing Clark County's EPA zone, it outranks 42% of them by population. Geologically, Clark County is grouped into EPA Region 6 alongside 502 other counties that share its rock and soil setting.

Zone vs. an actual test

Clark County's Zone 3 prediction undercuts the roughly 1.3 pCi/L most US homes average, nowhere near EPA's 4 pCi/L threshold for recommending mitigation. Low doesn't mean zero: EPA's own data shows homes in Zone 3 counties like Clark County testing above the action level often enough that skipping a test isn't the safe assumption.

Testing and mitigation in Clark County

Mitigation cost doesn't depend on Clark 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 Arkansas's state radon program

Clark County's test kit answers today; a Airthings radon monitor keeps answering for Clark 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. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.