What EPA's radon map says about Washington County

EPA's own radon map rates Washington County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Rank it against the rest of the country and Washington County lands in the 56th percentile for radon potential.

Where Washington County sits nationally

About 59,844 people live in Washington County, Vermont, spread over 687.06 square miles. That works out to roughly 87 people per square mile. Among counties sharing Washington County's EPA zone, it outranks 70% of them by population. Geologically, Washington County is grouped into EPA Region 1 alongside 58 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

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 Washington County's Zone 2 prediction. Washington County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

If Washington County tests above the action level

Mitigation cost doesn't depend on Washington 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 Vermont's state radon program

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

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed Washington County's numbers. Whatever zone Washington County carries, the zone explainer covers what it does and doesn't tell you about any one house.