Radon levels in Cook County, Illinois

LowEPA Zone 2

Predicted long-term basement average of 1.2 pCi/L (model estimate) across 161 ZIP codes - about 35% below the US average of 1.8, about 37% below the Illinois average of 1.9. Ranked #102 of 102 Illinois counties.

Test Cook County, IL once anyway - radon varies house to house

The predicted basement average here is 1.2 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.

1.2 ± 0.09

pCi/L predicted basement mean (model SD)

0.8 ± 0.09

pCi/L predicted upstairs (above-ground) mean

0.5-2.2

range of ZIP-level basement predictions in the county

What this means for Cook

The typical Cook 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 0.5 to 2.2 pCi/L.

Note that the EPA classifies Cook County as Zone 2 while the newer model predicts 1.2 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: Pulaski County (1.6), Massac County (1.7), Lake County (1.7), Wayne County (1.7). The state's highest is Knox County at 4.0 pCi/L.

ZIP codes in Cook County

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

ZIPBasementUpstairsGrade
606291.1 ± 0.080.7Low
606230.7 ± 0.090.7Low
606181.2 ± 0.070.8Low
606321.0 ± 0.070.7Low
606391.1 ± 0.080.9Low
606471.1 ± 0.140.7Low
608041.1 ± 0.070.7Low
606170.5 ± 0.140.5Low
606080.8 ± 0.090.7Low
606251.0 ± 0.120.7Low
606341.3 ± 0.060.9Low
606201.1 ± 0.090.7Low
606281.1 ± 0.070.7Low
606411.2 ± 0.070.8Low
606140.8 ± 0.150.6Low
606570.9 ± 0.090.6Low
606400.8 ± 0.090.5Low
606090.9 ± 0.070.6Low
606511.1 ± 0.100.7Low
606190.6 ± 0.100.5Low
604021.3 ± 0.070.8Low
600161.3 ± 0.150.9Low
604111.5 ± 0.061.0Low
604531.3 ± 0.071.1Low
600561.5 ± 0.081.1Low
606381.2 ± 0.090.9Low
606301.3 ± 0.070.9Low
606220.9 ± 0.090.7Low
601202.2 ± 0.051.5Moderate
600041.5 ± 0.071.2Low
606260.8 ± 0.080.5Low
606431.6 ± 0.081.0Low
606370.7 ± 0.090.5Low
606441.0 ± 0.090.7Low
606160.7 ± 0.130.6Low
606130.9 ± 0.090.6Low
606490.7 ± 0.120.5Low
606450.9 ± 0.080.7Low
600101.8 ± 0.081.6Low
602011.0 ± 0.150.8Low
607071.2 ± 0.060.9Low
606600.8 ± 0.080.5Low
606521.2 ± 0.070.9Low
606361.1 ± 0.070.7Low
606150.9 ± 0.070.6Low
600621.7 ± 0.081.1Low
601071.7 ± 0.091.3Low
601931.6 ± 0.091.1Low
600251.6 ± 0.081.1Low
600741.8 ± 0.091.1Low
604621.7 ± 0.081.2Low
600672.2 ± 0.071.4Moderate
604771.5 ± 0.101.2Low
606240.7 ± 0.210.7Low
606590.9 ± 0.070.6Low
606100.9 ± 0.120.6Low
600901.4 ± 0.070.9Low
600681.3 ± 0.071.0Low
604091.0 ± 0.090.7Low
606210.8 ± 0.090.5Low
601691.7 ± 0.071.2Low
600071.6 ± 0.071.1Low
606120.6 ± 0.150.6Low
600761.2 ± 0.100.9Low
603021.0 ± 0.150.8Low
602020.8 ± 0.120.7Low
605251.9 ± 0.081.2Low
600181.4 ± 0.061.1Low
607141.4 ± 0.061.0Low
606530.9 ± 0.070.6Low
604261.1 ± 0.070.8Low
600051.7 ± 0.081.0Low
604591.2 ± 0.070.9Low
604381.3 ± 0.060.9Low
606110.9 ± 0.110.5Low
606311.3 ± 0.081.1Low
606551.2 ± 0.070.9Low
604521.5 ± 0.071.2Low
608270.9 ± 0.060.7Low
606561.1 ± 0.070.8Low
606461.1 ± 0.140.9Low
600911.2 ± 0.091.1Low
604871.6 ± 0.081.3Low
600771.2 ± 0.060.9Low
604451.4 ± 0.081.1Low
604671.8 ± 0.061.2Low
604061.2 ± 0.070.7Low
601601.2 ± 0.060.8Low
606050.9 ± 0.090.6Low
601531.2 ± 0.060.8Low
606070.8 ± 0.110.6Low
600531.2 ± 0.111.0Low
607061.1 ± 0.080.9Low
604391.8 ± 0.111.3Low
604191.1 ± 0.090.8Low
600081.6 ± 0.091.2Low
604731.3 ± 0.111.0Low
608031.4 ± 0.061.0Low
604661.3 ± 0.070.7Low
601641.3 ± 0.060.9Low
604431.7 ± 0.061.1Low
604301.4 ± 0.071.1Low
608051.2 ± 0.060.9Low
601941.3 ± 0.121.0Low
600931.5 ± 0.111.1Low
605131.4 ± 0.080.9Low
601041.2 ± 0.090.9Low
606420.8 ± 0.110.6Low
601311.3 ± 0.060.9Low
604651.5 ± 0.061.1Low
603041.3 ± 0.091.0Low
604781.6 ± 0.061.2Low
601541.4 ± 0.061.0Low
604551.4 ± 0.061.1Low
601921.7 ± 0.071.5Low
600701.7 ± 0.101.0Low
605461.4 ± 0.100.9Low
604291.6 ± 0.051.1Low
606540.9 ± 0.100.6Low
604631.5 ± 0.101.2Low
604581.4 ± 0.060.9Low
601301.2 ± 0.080.8Low
604151.1 ± 0.070.8Low
604711.8 ± 0.061.2Low
604571.5 ± 0.051.1Low
605261.5 ± 0.121.0Low
600261.5 ± 0.071.0Low
605581.5 ± 0.081.2Low
606331.1 ± 0.070.7Low
607121.4 ± 0.061.1Low
601731.4 ± 0.080.9Low
604281.3 ± 0.070.8Low
601761.3 ± 0.060.9Low
605011.3 ± 0.060.9Low
603051.3 ± 0.081.0Low
606010.9 ± 0.090.4Low
604821.3 ± 0.060.9Low
605341.2 ± 0.070.8Low
601711.3 ± 0.070.8Low
604751.6 ± 0.061.1Low
604641.8 ± 0.071.3Low
604221.7 ± 0.051.3Low
604251.3 ± 0.061.0Low
600221.5 ± 0.061.1Low
601621.3 ± 0.060.8Low
601551.2 ± 0.070.8Low
604691.2 ± 0.061.0Low
604721.1 ± 0.080.8Low
604801.6 ± 0.061.1Low
601631.4 ± 0.070.9Low
601651.3 ± 0.060.9Low
604611.6 ± 0.061.2Low
601951.3 ± 0.171.1Low
602031.3 ± 0.061.0Low
604560.8 ± 0.080.8Low
600431.4 ± 0.061.2Low
604761.2 ± 0.070.8Low
606060.9 ± 0.100.5Low
606030.9 ± 0.080.5Low
600291.6 ± 0.061.1Low
601411.1 ± 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.

Cook County radon questions

Is radon high in Cook County, Illinois?
Low. The model predicts a long-term basement average of 1.2 pCi/L in Cook County (about 35% below the US average of 1.8 and about 37% below the Illinois average of 1.9). That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Ranked 102 of 102 Illinois counties.
Should I test for radon in Cook County?
Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Cook County already range from 0.5 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 Cook 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 1.2 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 Cook 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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