Radon Testing & Mitigation for Chicago's North Shore
Radon is an invisible, odorless radioactive gas that seeps from the soil into basements across Northbrook, Glenview, Wilmette, and Evanston. Nearly 30% of professionally tested Cook County homes come back at or above the EPA action level. We test, we install, and we verify the number came down, with a firm price before any work starts.
The county map says moderate. The test results say otherwise.
Cook County sits in EPA Radon Zone 2, the "moderate" band, with predicted indoor averages of 2 to 4 pCi/L. That sounds reassuring until you look at actual test results: per Illinois Emergency Management Agency data, nearly 30% of Cook County homes tested by licensed professionals measured at or above the EPA's 4.0 pCi/L action level, and over 40% did statewide. Radon doesn't follow zone maps. It follows the soil under your specific foundation, the cracks and sump openings in your specific basement, and the way your specific house breathes in winter.
The only way to know your number is a test. The good news: if the number is high, this is one of the most fixable problems a house can have.
What we handle
Radon Testing
Closed-house short-term tests, long-term tests, and continuous monitor measurements that stand up in a real estate deal.
Radon Mitigation
Sub-slab depressurization systems installed in a day, tagged and verified with a follow-up test.
Real Estate Testing
48-hour continuous monitor tests on inspection-window timelines, with same-day reports when the deal clock is running.
Why North Shore homes in particular
Illinois has required passive radon-resistant construction in new houses since June 2013. Almost none of the North Shore's housing stock is that new. Only about 21% of Northbrook's homes were built after 2000, and roughly 9 in 10 Glenview homes predate 2010. Wilmette's median house dates to 1957, and four in ten Evanston homes were built before 1940. That means the overwhelming majority of homes in our area went up decades before anyone thought about radon, with no built-in defense unless someone added a system later.
Older foundations also give radon more ways in: settling cracks, unsealed sump pits, floor drains, and the porous block and stone walls common in pre-war construction. Winter makes it worse, because a heated house pulls soil gas upward like a chimney while the windows stay shut.
What it costs
Most mitigation installs here run $800 to $2,500, with a typical single-family system landing around $1,200 to $1,500. Professional testing runs a small fraction of that, and Cook County's health department offers free short-term test kits to suburban residents, which we're happy to point you toward if you just want a first look at your number. When a licensed measurement matters, for a real estate deal or a post-mitigation verification, we handle it start to finish.
Licensed work, tagged and verified
Illinois has licensed radon professionals under the Radon Industry Licensing Act since 1998. Every system we arrange is installed by a state-licensed mitigation professional, carries the required tag on the vent pipe with the installer's name and license number, and gets a follow-up test to prove the level actually dropped. If a company quoting you can't show an Illinois license, that's your cue to keep looking.
Wondering what your basement's number is?
Call (224) 362-4440Frequently asked questions
What level of radon is dangerous?
The EPA action level is 4.0 picocuries per liter (pCi/L). At or above that number, the EPA recommends fixing the home; between 2.0 and 4.0, it recommends considering a fix. There is no established safe level, which is why testing is the only way to know where your house stands. Radon is invisible and odorless, so a dangerous basement feels exactly like a safe one.
How likely is a high reading on the North Shore?
More likely than the maps suggest. Cook County is mapped as a moderate radon zone, but per state data, nearly 30% of Cook County homes tested by licensed professionals came back at or above the 4.0 pCi/L action level. Two houses on the same block can test completely differently, so the county average tells you very little about your own basement.
What does radon mitigation cost?
Most single-family installs on the North Shore land between $800 and $2,500, with typical jobs around $1,200 to $1,500. The big variables are your foundation type, where the fan and vent pipe can run, and whether a crawlspace needs a sealed membrane. You get a firm quote before any drilling, and a post-install test verifies the number actually came down.
How long does the work take?
A standard sub-slab system is almost always a one-day install. Testing takes longer than the fix: a short-term closed-house test runs at least 48 hours, and the verification test after installation runs another two days. From first call to verified system, most homes are done inside two weeks.
Request a free quote
Tell us what you need — a test, a mitigation quote, or a deal-deadline measurement — and we'll get back to you shortly.