Radon levels in Dane County, Wisconsin

LowEPA Zone 1

Predicted long-term basement average of 1.8 pCi/L (model estimate) across 32 ZIP codes - close to the US average of 1.8, close to the Wisconsin average of 2.0. Ranked #63 of 72 Wisconsin counties.

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

The predicted basement average here is 1.8 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.

1.8 ± 0.09

pCi/L predicted basement mean (model SD)

1.4 ± 0.06

pCi/L predicted upstairs (above-ground) mean

1.1-3.0

range of ZIP-level basement predictions in the county

What this means for Dane

The typical Dane 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 1.1 to 3.0 pCi/L.

Note that the EPA classifies Dane County as Zone 1 while the newer model predicts 1.8 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: Bayfield County (1.8), Sawyer County (1.8), Iron County (1.8), Burnett County (1.8). The state's highest is Lafayette County at 3.4 pCi/L.

ZIP codes in Dane County

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

ZIPBasementUpstairsGrade
537111.7 ± 0.081.5Low
537041.5 ± 0.091.2Low
535901.6 ± 0.101.6Low
537191.1 ± 0.121.1Low
537031.4 ± 0.060.9Low
535621.6 ± 0.101.2Low
537052.2 ± 0.081.3Moderate
537131.8 ± 0.081.1Low
535891.9 ± 0.091.7Low
535931.7 ± 0.091.6Low
537162.0 ± 0.091.2Moderate
535971.4 ± 0.091.2Low
537141.5 ± 0.121.1Low
535752.0 ± 0.091.8Low
535321.8 ± 0.111.8Low
537151.6 ± 0.060.9Low
537171.8 ± 0.071.6Low
537181.5 ± 0.121.4Low
535582.0 ± 0.101.3Low
535723.1 ± 0.092.1Moderate
535271.8 ± 0.111.7Low
535592.7 ± 0.071.9Moderate
535282.4 ± 0.062.0Moderate
535082.8 ± 0.052.1Moderate
537261.6 ± 0.061.0Low
535232.5 ± 0.062.0Moderate
535312.4 ± 0.062.0Moderate
535602.1 ± 0.051.2Moderate
535981.9 ± 0.061.6Low
535152.9 ± 0.052.1Moderate
535292.0 ± 0.051.4Moderate
535172.9 ± 0.062.2Moderate

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.

Dane County radon questions

Is radon high in Dane County, Wisconsin?
Low. The model predicts a long-term basement average of 1.8 pCi/L in Dane County (close to the US average of 1.8 and close to the Wisconsin average of 2.0). That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Ranked 63 of 72 Wisconsin counties.
Should I test for radon in Dane County?
Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Dane County already range from 1.1 to 3.0 pCi/L. A short-term kit costs little and settles the question for your house.
What does EPA Radon Zone 1 mean for Dane 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 1.8 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 Dane 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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