St. Francis County, AR: EPA's radon zone, explained

EPA's own radon map rates St. Francis County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. Nationally that's the 14th percentile for radon potential — St. Francis County outranks 14% of every county EPA has rated.

St. Francis County by the numbers

St. Francis County, Arkansas is home to about 21,822 people across 634.784 square miles. Population density there runs about 34 people per square mile. By population, St. Francis County is the 583rd largest of every county sharing its EPA zone — the 43rd percentile by population within that zone. EPA's geology-based Region 6 groups St. Francis County with 502 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

St. Francis 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. Even at Zone 3, St. Francis County homes are not guaranteed a low reading — zone is a county-wide average, and EPA recommends testing every home regardless of zone.

If St. Francis County tests above the action level

For a St. Francis County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find Arkansas's state radon program

For St. Francis County, an ongoing number beats a one-time test - a Airthings radon monitor tracks St. Francis County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

Where St. Francis County's figures come from

The methodology guide shows exactly which EPA and Census sources feed St. Francis County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.