46%tests ≥ 4 pCi/L
23,315tests on record
3.5median pCi/L
Zone 1EPA zone (1993 prediction)

Test results in Waukesha County

ResultShareEPA guidance
Below 2 pCi/L36%Below EPA's levels
2 to 4 pCi/L17%Consider fixing
4 pCi/L or more46%EPA recommends fixing

What the data shows

Where Waukesha County sits among Wisconsin's 72 counties with dataEach dot is a county's share of tests at or above 4 pCi/L · Wisconsin county radon test results, 2005–2017
0%20%40%60%

How Waukesha County compares

Waukesha County ranks 3 of 8 among its neighboursShare of tests at or above 4 pCi/L · Wisconsin county radon test results, 2005–2017 · whisker: 95% range
Dodge County54%Walworth County49%Waukesha County46%Racine County46%Washington County46%Jefferson County39%Ozaukee County39%Milwaukee County33%Wisconsin 42%
Data table
AreaTests ≥ 4 pCi/LTests
Dodge County54%2,208
Walworth County49%3,690
Waukesha County46%23,315
Racine County46%6,151
Washington County46%5,615
Jefferson County39%2,157
Ozaukee County39%4,401
Milwaukee County33%20,170
Wisconsin (72 counties)42%194,443

Same source as Waukesha County.

What it means for your home

About 1 in 2 results in Waukesha County were at or above 4 pCi/L, where the EPA recommends a fix. Only a test shows your own home's level.

Levels in pCi/L from the EPA. The WHO reference level is 100 Bq/m³, about 2.7 pCi/L.

Test your home

Start with a short-term test (2–90 days) and confirm a result of 4 pCi/L or more with a second test. EPA guide

Sponsored: we earn a commission on purchases through these links. We haven't tested Airthings monitors yet.

Prefer a digital monitor? See Airthings radon monitors, or enter code radonbycounty-10OFF at their discount store for 10% off.

Fixing high radon

No local job records yet. National range: $800–$2,500, average $1,200 (EPA, 2003). Cost guide →

Wisconsin doesn't license radon mitigators; look for NRPP or NRSB certification. Source

Buying or selling here

Wisconsin sellers must tell buyers about any known unsafe radon levels through the Real Estate Condition Report (Wis. Stat. § 709.03). Source

Checked against the official text on 2026-11-03. Not legal advice.

About this data

Source: Wisconsin county radon test results (Wisconsin Department of Health Services). Period: 2005–2017. Tests: 23,315. Read the methodology →

These are voluntary and real-estate tests, not a random sample of homes, so they describe tested homes rather than every home.

About this page

Published by Ray Roman, editor of Radon by County. Figures are loaded from the cited source and spot-checked against it. Editorial policy · About us