Washington County, UT radon potential

Washington 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 Washington County in the 62nd percentile nationally for radon potential — higher than 62% of the counties EPA has rated.

Washington County by the numbers

Washington County, Utah is home to about 207,943 people across 2,427.589 square miles. Averaged across its land area, Washington County runs about 86 people per square mile. Within its own EPA zone, Washington County is bigger by population than 89% of the counties that share it. Washington County falls in EPA Radon Region 8, one of 291 counties nationally EPA assigns to that same geologic province.

Why the zone isn't the answer by itself

EPA's Zone 2 rating for Washington County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. 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.

Next steps for a home in Washington County

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find Utah's state radon program

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

Washington County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.