Is radon high in Waukesha County, Wisconsin?

Low. The model predicts a long-term basement average of 1.6 pCi/L in Waukesha County (close to the US average of 1.8 and about 21% 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 67 of 72 Wisconsin counties.

Should I test for radon in Waukesha County?

Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Waukesha County already range from 1.2 to 2.3 pCi/L. A short-term kit costs little and settles the question for your house.

What does EPA Radon Zone 1 mean for Waukesha County?

Zone 1 - highest potential (predicted average > 4 pCi/L). The zone map dates from 1993 and classifies whole counties. The newer model's predicted average of 1.6 pCi/L does not line up with Zone 1, 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 Waukesha 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.

Radon levels in Waukesha County, Wisconsin

LowEPA Zone 1

Predicted long-term basement average of 1.6 pCi/L (model estimate) across 25 ZIP codes - close to the US average of 1.8, about 21% below the Wisconsin average of 2.0. Ranked #67 of 72 Wisconsin counties.

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

The predicted basement average here is 1.6 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.

Get a short-term test kit →Or track it with a continuous monitor

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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.

1.6 ± 0.10

pCi/L predicted basement mean (model SD)

1.4 ± 0.07

pCi/L predicted upstairs (above-ground) mean

1.2-2.3

range of ZIP-level basement predictions in the county

What this means for Waukesha

The typical Waukesha 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 1.2 to 2.3 pCi/L.

Note that the EPA classifies Waukesha County as Zone 1 while the newer model predicts 1.6 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: Manitowoc County (1.6), Marinette County (1.6), Ashland County (1.5), Ozaukee County (1.5). The state's highest is Lafayette County at 3.4 pCi/L.

ZIP codes in Waukesha County

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

ZIP	Basement	Upstairs	Grade
53051	1.6 ± 0.08	1.6	Low
53188	1.3 ± 0.09	1.3	Low
53066	1.7 ± 0.10	1.5	Low
53186	1.2 ± 0.09	1.2	Low
53151	1.4 ± 0.09	1.0	Low
53189	1.6 ± 0.11	1.6	Low
53150	1.9 ± 0.09	1.3	Low
53072	1.3 ± 0.09	1.4	Low
53045	1.4 ± 0.10	1.3	Low
53029	2.1 ± 0.12	1.8	Moderate
53005	1.6 ± 0.10	1.2	Low
53149	1.5 ± 0.11	1.5	Low
53089	1.6 ± 0.12	1.5	Low
53018	2.3 ± 0.11	1.8	Moderate
53146	1.7 ± 0.09	1.4	Low
53118	2.0 ± 0.11	1.8	Moderate
53122	1.8 ± 0.08	1.4	Low
53119	2.0 ± 0.18	1.9	Moderate
53103	2.2 ± 0.08	1.8	Moderate
53058	1.9 ± 0.07	1.6	Low
53183	2.3 ± 0.09	1.7	Moderate
53153	1.8 ± 0.08	1.6	Low
53007	1.7 ± 0.07	1.3	Low
53046	1.7 ± 0.06	1.4	Low
53069	1.9 ± 0.06	1.6	Low

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.

Waukesha County radon questions

Is radon high in Waukesha County, Wisconsin?: Low. The model predicts a long-term basement average of 1.6 pCi/L in Waukesha County (close to the US average of 1.8 and about 21% 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 67 of 72 Wisconsin counties.
Should I test for radon in Waukesha County?: Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Waukesha County already range from 1.2 to 2.3 pCi/L. A short-term kit costs little and settles the question for your house.
What does EPA Radon Zone 1 mean for Waukesha County?: Zone 1 - highest potential (predicted average > 4 pCi/L). The zone map dates from 1993 and classifies whole counties. The newer model's predicted average of 1.6 pCi/L does not line up with Zone 1, 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 Waukesha 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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