What EPA's radon map says about Orange County

Orange County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. Nationally, Orange County ranks higher in radon potential than 32% of rated counties (the 32nd percentile).

How Orange County compares

About 1,533,646 people live in Orange County, Florida, spread over 903.053 square miles. Population density there runs about 1,698 people per square mile. Among counties sharing Orange County's EPA zone, it outranks 98% of them by population. EPA's geology-based Region 4 groups Orange County with 735 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Orange County

At Zone 3, Orange 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 Orange 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 Orange County tests above the action level

Mitigation cost doesn't depend on Orange 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 Florida's state radon program

Orange County's test kit answers today; a Airthings radon monitor keeps answering for Orange County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

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.