Franklin County, FL: EPA's radon zone, explained

EPA places Franklin County in Zone 3 - Low Potential — a predicted county-wide average indoor radon level below 2 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Franklin County sits at the 9th percentile nationally for radon potential — above 9 of every 100 rated counties.

Franklin County by the numbers

Franklin County, Florida is home to about 12,979 people across 545.002 square miles. That works out to roughly 24 people per square mile. By population, Franklin County is the 753rd largest of every county sharing its EPA zone — the 27th percentile by population within that zone. Geologically, Franklin County is grouped into EPA Region 4 alongside 735 other counties that share its rock and soil setting.

Zone vs. an actual test

A Zone 3 county like Franklin County is predicted closer to the 0.4 pCi/L typical outdoors than to EPA's 4 pCi/L action level. A Zone 3 label describes Franklin County's average, not any one basement or slab in it — testing is still the only way an individual homeowner actually finds out.

Testing and mitigation in Franklin County

For a Franklin 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 Florida's state radon program

For Franklin County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Franklin 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 Franklin County's figures come from

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Franklin County carries, the zone explainer covers what it does and doesn't tell you about any one house.