What EPA's radon map says about Ozaukee County

Ozaukee 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 Ozaukee County in the 59th percentile nationally for radon potential — higher than 59% of the counties EPA has rated.

Where Ozaukee County sits nationally

About 93,956 people live in Ozaukee County, Wisconsin, spread over 233.011 square miles. Averaged across its land area, Ozaukee County runs about 403 people per square mile. Among counties sharing Ozaukee County's EPA zone, it outranks 79% of them by population. Ozaukee County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

EPA's Zone 2 rating for Ozaukee County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. A county-wide moderate average, like Ozaukee County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Testing and mitigation in Ozaukee County

Mitigation cost doesn't depend on Ozaukee 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 Wisconsin's state radon program

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

Ozaukee 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.