Radon levels in Will County, Illinois

ModerateEPA Zone 2

Predicted long-term basement average of 2.1 pCi/L (model estimate) across 30 ZIP codes - about 1.2× the US average of 1.8, close to the Illinois average of 1.9. Ranked #70 of 102 Illinois counties.

Test Will County, IL - the EPA says "consider fixing" in this range

The predicted basement average here is 2.1 pCi/L, in the 2-4 pCi/L band where the EPA recommends considering mitigation. Plenty of individual homes in a moderate area test above 4. Start with a short-term test; if it comes back at 2 or higher, follow up with a long-term test or a continuous monitor.

Already tested at 4 pCi/L or higher? Find a certified mitigation professional (EPA). A mitigation system typically runs $800-$2,500 installed.

We may earn a commission from Amazon at no extra cost to you.

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.

2.1 ± 0.09

pCi/L predicted basement mean (model SD)

1.4 ± 0.08

pCi/L predicted upstairs (above-ground) mean

1.4-3.7

range of ZIP-level basement predictions in the county

What this means for Will

The typical Will County home is predicted in the 2-4 pCi/L band. The EPA's guidance for this range is to consider fixing, because there is no known safe level and roughly one home in several in a moderate area will test above 4.

The 1993 EPA zone (2) and the 2001-2021 model agree for Will. County figures weight each ZIP by its 2010 Census population, so they describe where people live rather than empty land.

Comparable Illinois counties: Perry County (2.1), Bond County (2.2), Clark County (2.1), McHenry County (2.1). The state's highest is Knox County at 4.0 pCi/L.

ZIP codes in Will County

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

ZIPBasementUpstairsGrade
604401.8 ± 0.101.3Low
604352.4 ± 0.101.6Moderate
605862.3 ± 0.091.5Moderate
605641.6 ± 0.081.3Low
604462.2 ± 0.091.5Moderate
604412.0 ± 0.071.2Moderate
604512.7 ± 0.101.4Moderate
604231.9 ± 0.061.3Low
605442.5 ± 0.111.6Moderate
604481.8 ± 0.091.2Low
604911.8 ± 0.111.3Low
604312.2 ± 0.091.6Moderate
605852.0 ± 0.091.4Low
604322.2 ± 0.061.4Moderate
604902.2 ± 0.081.6Moderate
604362.1 ± 0.091.2Moderate
604032.2 ± 0.061.5Moderate
604042.2 ± 0.101.6Moderate
604332.3 ± 0.061.4Moderate
605031.7 ± 0.111.4Low
604171.5 ± 0.081.2Low
604103.7 ± 0.121.7Moderate
604812.6 ± 0.061.6Moderate
604422.7 ± 0.071.7Moderate
604492.0 ± 0.061.3Moderate
604011.9 ± 0.081.3Low
604841.9 ± 0.061.1Low
604682.7 ± 0.061.7Moderate
604082.4 ± 0.061.5Moderate
604212.6 ± 0.061.6Moderate

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.

Will County radon questions

Is radon high in Will County, Illinois?
Moderate. The model predicts a long-term basement average of 2.1 pCi/L in Will County (about 1.2× the US average of 1.8 and close to the Illinois average of 1.9). That is in the 2-4 pCi/L range where the EPA recommends considering mitigation. Ranked 70 of 102 Illinois counties.
Should I test for radon in Will County?
Yes, soon. With a predicted average of 2.1 pCi/L, many homes in Will County will test above the 4 pCi/L action level. Use a short-term kit first; if it reads 2 or higher, confirm with a long-term test or continuous monitor before deciding on mitigation.
What does EPA Radon Zone 2 mean for Will County?
Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and classifies whole counties. The 2001-2021 model agrees with the zone here. Neither replaces a test of your own home.
How much does radon mitigation cost in Will 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.

← All Illinois counties · How to test · Radon in a home sale · Methodology