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

EPA's own radon map rates Flagler County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. Rank it against the rest of the country and Flagler County lands in the 27th percentile for radon potential.

Where Flagler County sits nationally

Flagler County, Florida is home to about 136,744 people across 486.191 square miles. That works out to roughly 281 people per square mile. By population, Flagler County is the 179th largest of every county sharing its EPA zone — the 83rd percentile by population within that zone. Geologically, Flagler County is grouped into EPA Region 4 alongside 735 other counties that share its rock and soil setting.

What this actually means for a house in Flagler County

At Zone 3, Flagler County's predicted county average is under the national indoor average (~1.3 pCi/L) and well below EPA's 4 pCi/L action level — outdoor air nationally runs about 0.4 pCi/L for comparison. A Zone 3 rating means Flagler 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.

Testing and mitigation in Flagler County

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

The methodology guide shows exactly which EPA and Census sources feed Flagler County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.