How to Test Your DuPage County Home for Radon

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Across DuPage County, from 1920s bungalows in Elmhurst to 1990s two-stories in Lisle, the only way to learn your home's radon level is to measure it. Two houses side by side can get very different results. A test is cheap, takes a few days and mostly means leaving a small kit alone.

Below: where to get an inexpensive kit, the setup rules that keep the number honest, and how to read the lab report. We are a free referral service that connects homeowners with licensed mitigators. We don't sell kits or do radon work ourselves.

Short version: buy a short-term kit, test the lowest level you regularly use for at least 48 hours with windows and doors closed, and mail it back. If the result is 4.0 pCi/L or higher, the U.S. EPA recommends fixing the home.

Why test?

The American Lung Association calls radon the second leading cause of lung cancer in the U.S. In Illinois, IEMA data cited by the Lung Association put the average indoor level at 5.1 pCi/L, above the EPA action level, with about 45% of homes tested at or above 4 pCi/L. Your neighbor's result can't tell you yours.

Short-term vs. long-term tests

Type	How long	Best for
Short-term (charcoal or liquid scintillation)	At least 48 hours, usually 2 to 7 days	A first test, a quick answer, a follow-up after a high result, or checking a mitigation system
Long-term (alpha track)	More than 90 days	A truer year-round average, because radon changes day to day and season to season

Where to get a low-cost kit

IEMA-OHS (the state radon program) publishes a list of licensed labs that sell kits by mail. According to IEMA, the listed prices include the detector, return packaging and postage, all lab fees and a mailed report. IEMA doesn't endorse one lab over another and says to confirm the price before you buy.

Licensed lab (IEMA list)	Kit type	IEMA-listed price
Radon Testing Corporation of America	Liquid scintillation (short-term)	$6.95
Air Chek	Charcoal (short-term) / alpha track (long-term)	$7.95 / $21.95
Alpha Energy Laboratories	Charcoal (short-term)	$10.95
RSSI (Morton Grove, IL)	Charcoal (short-term) / alpha track (long-term)	$15.00 / $25.00
AccuStar Labs	Charcoal, liquid scintillation, alpha track	$25.00 to $30.00

Prices from the IEMA-OHS low-cost detector list, checked October 29, 2026. Labs set their own prices, so confirm with the lab before ordering.

American Lung Association: the Lung Association in Illinois and IEMA-OHS offer discounted short-term kits to Illinois residents while supplies last at Lung.org/radon-test or through the Illinois Radon HelpLine, 800-325-1245. The Lung Association lists its Illinois long-term alpha track kit at $38, shipping included.
Hardware and home stores: most carry kits. IEMA-OHS says kits typically cost $15 to $25, usually including lab analysis. Check whether the lab fee is included.
A licensed professional: IEMA-OHS puts a licensed professional test at about $150 to $250. That's the recommended route for a home sale.

How to test correctly

Close up the house 12 hours before you start and keep it closed during the test. Keep windows shut, use doors only for normal coming and going, and don't run fans that bring in outside air. Heat and AC can run normally.
Pick the lowest level you regularly use, like a family room, bedroom or playroom. Skip kitchens, bathrooms, laundry rooms and crawl spaces, and don't put the kit next to a sump pit or a floor crack.
Place it 20 inches to 6 feet off the floor, at least 3 feet from outside doors and windows and 1 foot from exterior walls, away from drafts, heat, sun and humidity.
Leave it alone for at least 48 hours (or as long as the instructions say). Avoid testing during or right after a severe storm or high winds.
Reseal it and mail it back right away. Write the start and stop times on the form. Results usually arrive within a few weeks.

Testing tips for DuPage homes

Many older homes in Wheaton, Glen Ellyn and Downers Grove have partly finished or stone-and-block basements. If anyone spends regular time down there, for laundry-room hangouts, a home office or a playroom, test there. If the basement is storage only, test the lowest floor you live on. Homes with a crawl space plus a basement (common in additions) should get one kit per foundation area, as the Lung Association suggests.

Reading your result

Result	What the EPA recommends
Below 2 pCi/L	No action needed. Retest every couple of years or after major renovations.
2 to 3.9 pCi/L	Consider fixing. A long-term test gives a clearer picture.
4.0 pCi/L or higher	Fix the home. Confirm with a follow-up test, then hire an IEMA-licensed mitigator.

Over 4.0? Get a free mitigation quote

Tell us your result and town. We'll connect you with an independent, IEMA-licensed radon mitigator who serves DuPage County. The referral is free and you're under no obligation.

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Curious about price first? See our mitigation cost guide.

Buying or selling a home?

Under the Illinois Radon Awareness Act, a seller must give the buyer the IEMA pamphlet "Radon Testing Guidelines for Real Estate Transactions" and the Illinois Disclosure of Information on Radon Hazards before the buyer is bound by a contract, and must disclose any elevated radon results the seller has. The law doesn't require the seller to test or mitigate. IEMA-OHS recommends having a licensed measurement professional do the test for a sale.

Good timing: January is National Radon Action Month

The EPA and the Illinois radon program promote testing every January. Winter is also when Illinois homes are closed up most, which makes closed-house conditions easy.

Radon testing FAQ

Can I test my own home for radon in Illinois?

Yes. Illinois lets you measure the home you live in without a license. For a home sale, IEMA-OHS recommends using a licensed radon measurement professional.

How long does a radon test take?

Short-term kits stay in place at least 48 hours and usually 2 to 7 days. Long-term kits stay more than 90 days and give a better year-round average.

What radon level is too high?

The U.S. EPA recommends fixing your home at 4.0 pCi/L or higher and considering a fix between 2 and 4 pCi/L.

Should I retest before fixing?

If a short-term result is 4.0 or higher, the Illinois Radon HelpLine (800-325-1245) can advise on a follow-up test to confirm before you hire a mitigator.

Do you sell test kits or do testing?

No. We are a free referral service. Buy kits directly from a lab or the Lung Association. If you need mitigation, we can connect you with an independent IEMA-licensed mitigator.