What EPA's radon map says about Franklin County

EPA places Franklin County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally that's the 58th percentile for radon potential — Franklin County outranks 58% of every county EPA has rated.

Where Franklin County sits nationally

About 79,771 people live in Franklin County, North Carolina, spread over 491.874 square miles. Averaged across its land area, Franklin County runs about 162 people per square mile. Among counties sharing Franklin County's EPA zone, it outranks 77% of them by population. Franklin County falls in EPA Radon Region 4, one of 736 counties nationally EPA assigns to that same geologic province.

What this actually means for a house in Franklin County

Call it a middle case: above the 1.3 pCi/L most US homes average, below the 4 pCi/L line EPA uses to recommend mitigation — that's Franklin County's Zone 2 prediction. Nothing about a Zone 2 label lowers the case for testing in Franklin County — EPA recommends it in every zone, moderate included.

If Franklin County tests above the action level

Mitigation cost doesn't depend on Franklin 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 North Carolina's state radon program

Franklin County's test kit answers today; a Airthings radon monitor keeps answering for Franklin 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

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