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

Franklin County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. That puts Franklin County in the 55th percentile nationally for radon potential — higher than 55% of the counties EPA has rated.

Where Franklin County sits nationally

Franklin County, Vermont is home to about 51,066 people across 630.961 square miles. That works out to roughly 81 people per square mile. By population, Franklin County is the 340th largest of every county sharing its EPA zone — the 67th percentile by population within that zone. Geologically, Franklin County is grouped into EPA Region 1 alongside 58 other counties that share its rock and soil setting.

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. Middle-of-the-pack doesn't mean risk-free for any one Franklin County address — a moderate county average still leaves individual homes to test either side of it.

If Franklin County tests above the action level

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 Vermont'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. Code RADONZONE-10OFF takes 10% off at checkout.

Where Franklin County's figures come from

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.