Is Washburn County, WI a radon risk area?

EPA places Washburn 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 44th percentile for radon potential — Washburn County outranks 44% of every county EPA has rated.

Where Washburn County sits nationally

About 16,982 people live in Washburn County, Wisconsin, spread over 797.114 square miles. Averaged across its land area, Washburn County runs about 21 people per square mile. Rank 674 by population within its EPA zone puts Washburn County at the 35th percentile among zone peers. Washburn County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Neither at the 4 pCi/L action level nor down at the roughly 1.3 pCi/L national indoor norm, Washburn County's Zone 2 prediction lands in the gap between the two. Nothing about a Zone 2 label lowers the case for testing in Washburn County — EPA recommends it in every zone, moderate included.

If Washburn County tests above the action level

Nothing about Washburn County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find Wisconsin's state radon program

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

More on how this number was built

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