Jefferson County, AR radon potential

Jefferson County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. Nationally, Jefferson County ranks higher in radon potential than 24% of rated counties (the 24th percentile).

Jefferson County by the numbers

Jefferson County, Arkansas is home to about 63,672 people across 872.346 square miles. Population density there runs about 73 people per square mile. Within its own EPA zone, Jefferson County is bigger by population than 72% of the counties that share it. Geologically, Jefferson County is grouped into EPA Region 6 alongside 502 other counties that share its rock and soil setting.

Zone vs. an actual test

Jefferson County's predicted average sits below the national indoor average of about 1.3 pCi/L, well under EPA's 4 pCi/L action level. A Zone 3 rating means Jefferson County's county-wide average is predicted low, but EPA is explicit that a meaningful share of homes in low-potential zones still test above the action level — a low zone is not a reason to skip testing.

If Jefferson County tests above the action level

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find Arkansas's state radon program

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

Where Jefferson County's figures come from

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