Radon levels in Milwaukee County, Wisconsin

LowEPA Zone 2

Predicted long-term basement average of 1.3 pCi/L (model estimate) across 35 ZIP codes - about 30% below the US average of 1.8, about 38% below the Wisconsin average of 2.0. Ranked #72 of 72 Wisconsin counties.

Test Milwaukee County, WI once anyway - radon varies house to house

The predicted basement average here is 1.3 pCi/L, below the EPA's 2 pCi/L "consider fixing" threshold. That's good news for the area - but the EPA still recommends every home be tested, because foundation cracks, soil pockets and ventilation make one house very different from its neighbor. One inexpensive kit settles it.

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Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. How the numbers work.

1.3 ± 0.09

pCi/L predicted basement mean (model SD)

0.8 ± 0.09

pCi/L predicted upstairs (above-ground) mean

1.0-2.0

range of ZIP-level basement predictions in the county

What this means for Milwaukee

The typical Milwaukee County home is predicted below 2 pCi/L, the lowest band. That is the best case an area can show - but it describes the average house, and the ZIP-level predictions within the county still span 1.0 to 2.0 pCi/L.

Note that the EPA classifies Milwaukee County as Zone 2 while the newer model predicts 1.3 pCi/L. The zone map predates two decades of test data; where they disagree, we grade on the model but show both. County figures weight each ZIP by its 2010 Census population, so they describe where people live rather than empty land.

Comparable Wisconsin counties: Sheboygan County (1.5), Douglas County (1.5), Ozaukee County (1.5), Ashland County (1.5). The state's highest is Lafayette County at 3.4 pCi/L.

ZIP codes in Milwaukee County

Predicted basement and upstairs means by ZIP (model estimate). ZIPs whose land is mostly in this county.

ZIPBasementUpstairsGrade
532151.1 ± 0.120.6Low
532091.1 ± 0.110.8Low
532041.1 ± 0.070.6Low
532181.1 ± 0.070.6Low
532211.3 ± 0.091.0Low
532111.4 ± 0.070.7Low
532071.3 ± 0.100.7Low
531321.6 ± 0.071.5Low
532141.2 ± 0.090.8Low
531541.3 ± 0.101.2Low
532191.0 ± 0.100.7Low
532161.0 ± 0.160.6Low
532081.1 ± 0.080.5Low
532121.3 ± 0.090.7Low
532231.3 ± 0.120.8Low
532171.3 ± 0.070.9Low
532061.3 ± 0.110.5Low
532101.1 ± 0.080.7Low
532202.0 ± 0.101.0Low
532131.3 ± 0.070.9Low
532251.2 ± 0.100.9Low
532221.2 ± 0.090.8Low
532021.0 ± 0.070.5Low
532271.3 ± 0.121.0Low
532241.6 ± 0.061.0Low
531721.4 ± 0.091.0Low
532261.6 ± 0.121.1Low
531101.3 ± 0.120.9Low
532331.1 ± 0.070.6Low
532281.6 ± 0.111.0Low
531291.4 ± 0.101.3Low
532051.2 ± 0.060.6Low
532351.4 ± 0.070.9Low
531301.5 ± 0.091.3Low
532031.1 ± 0.070.6Low

If your test comes back at 4 pCi/L or higher

Mitigation is a routine job: a fan-driven pipe that vents soil gas from under the slab to above the roofline, typically $800-$2,500 installed (typical range; local quotes vary). Use certified professionals: EPA find-a-professional. Read the full mitigation guide.

Milwaukee County radon questions

Is radon high in Milwaukee County, Wisconsin?
Low. The model predicts a long-term basement average of 1.3 pCi/L in Milwaukee County (about 30% below the US average of 1.8 and about 38% below the Wisconsin average of 2.0). That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Ranked 72 of 72 Wisconsin counties.
Should I test for radon in Milwaukee County?
Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Milwaukee County already range from 1.0 to 2.0 pCi/L. A short-term kit costs little and settles the question for your house.
What does EPA Radon Zone 2 mean for Milwaukee County?
Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and classifies whole counties. The newer model's predicted average of 1.3 pCi/L does not line up with Zone 2, which is common - the EPA itself says high-radon homes exist in every zone. Neither replaces a test of your own home.
How much does radon mitigation cost in Milwaukee County?
A standard active sub-slab depressurization system typically runs $800-$2,500 installed nationally; Wisconsin quotes vary with foundation type (slab, crawlspace, basement), home size and local labor. Get two or three bids from certified mitigators listed by your state radon program or the EPA's find-a-professional page.

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