Radon levels in DuPage County, Illinois

LowEPA Zone 2

Predicted long-term basement average of 1.8 pCi/L (model estimate) across 36 ZIP codes - close to the US average of 1.8, close to the Illinois average of 1.9. Ranked #96 of 102 Illinois counties.

Test DuPage County, IL 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 ± 0.08

pCi/L predicted basement mean (model SD)

1.2 ± 0.07

pCi/L predicted upstairs (above-ground) mean

1.5-2.2

range of ZIP-level basement predictions in the county

What this means for DuPage

The typical DuPage 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 1.5 to 2.2 pCi/L.

Note that the EPA classifies DuPage County as Zone 2 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 Illinois counties: Alexander County (1.7), Wayne County (1.7), Gallatin County (1.9), Saline County (1.9). The state's highest is Knox County at 4.0 pCi/L.

ZIP codes in DuPage County

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

ZIPBasementUpstairsGrade
601481.8 ± 0.091.1Low
601261.6 ± 0.071.3Low
605402.0 ± 0.071.1Moderate
601881.9 ± 0.101.1Low
601031.8 ± 0.081.4Low
605651.9 ± 0.091.1Low
601011.6 ± 0.061.2Low
601331.8 ± 0.061.1Low
605041.9 ± 0.121.4Low
601371.7 ± 0.101.2Low
601851.8 ± 0.061.3Low
605631.7 ± 0.111.5Low
601391.6 ± 0.061.0Low
605171.7 ± 0.071.0Low
601891.5 ± 0.101.0Low
605161.7 ± 0.091.2Low
601871.5 ± 0.091.2Low
601811.7 ± 0.051.1Low
605151.9 ± 0.081.1Low
605271.8 ± 0.081.0Low
605321.9 ± 0.080.9Low
605591.8 ± 0.080.9Low
601721.7 ± 0.101.3Low
605611.8 ± 0.061.2Low
601082.2 ± 0.071.2Moderate
605021.8 ± 0.091.4Low
601061.6 ± 0.061.1Low
605211.9 ± 0.061.1Low
601911.7 ± 0.061.2Low
605552.0 ± 0.101.4Low
601901.7 ± 0.071.2Low
601431.7 ± 0.061.3Low
605231.7 ± 0.061.1Low
605141.7 ± 0.061.1Low
601842.2 ± 0.061.7Moderate
601571.8 ± 0.061.3Low

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.

DuPage County radon questions

Is radon high in DuPage County, Illinois?
Low. The model predicts a long-term basement average of 1.8 pCi/L in DuPage County (close to the US average of 1.8 and close to the Illinois average of 1.9). That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Ranked 96 of 102 Illinois counties.
Should I test for radon in DuPage County?
Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in DuPage County already range from 1.5 to 2.2 pCi/L. A short-term kit costs little and settles the question for your house.
What does EPA Radon Zone 2 mean for DuPage 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 1.8 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 DuPage County?
A standard active sub-slab depressurization system typically runs $800-$2,500 installed nationally; Illinois 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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