Is Milwaukee County, WI a radon risk area?

EPA's own radon map rates Milwaukee 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 Milwaukee County lands in the 65th percentile for radon potential.

How Milwaukee County compares

About 924,740 people live in Milwaukee County, Wisconsin, spread over 241.457 square miles. Averaged across its land area, Milwaukee County runs about 3,830 people per square mile. Rank 21 by population within its EPA zone puts Milwaukee County at the 98th percentile among zone peers. Geologically, Milwaukee County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

Zone vs. an actual test

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 Milwaukee County's Zone 2 prediction. Middle-of-the-pack doesn't mean risk-free for any one Milwaukee County address — a moderate county average still leaves individual homes to test either side of it.

If Milwaukee County tests above the action level

Nothing about Milwaukee 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

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

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Milwaukee County carries, the zone explainer covers what it does and doesn't tell you about any one house.