Illinois and Indiana both sit in EPA Radon Zone 1, the highest-risk category in the country. Testing is the only way to know what's in the air you're breathing. Here's what every homeowner needs to understand.
What Is Radon?
Radon is a colorless, odorless, tasteless radioactive gas that occurs naturally in the soil. It's produced when uranium in rock and dirt breaks down. Outside, it disperses harmlessly into the atmosphere. Inside, it can accumulate to dangerous concentrations, especially in basements and lower levels.
According to the EPA, radon exposure is the second leading cause of lung cancer in the United States, after smoking. It causes an estimated 21,000 lung cancer deaths every year.
Why Illinois and Indiana Are High-Risk
Both states are in EPA Radon Zone 1, where the predicted average indoor radon level exceeds the action threshold of 4.0 pCi/L (picocuries per liter).
The reason is geological:
- The bedrock and soil under much of the Midwest contains higher concentrations of uranium
- Long winters mean homes are sealed up for months at a time, allowing radon to accumulate
- Many homes have basements, which are in direct contact with the soil
- Older homes often have cracks in foundations and slab penetrations that let radon enter
The Illinois Emergency Management Agency estimates that about 40% of homes in Illinois have radon levels above the EPA action level. Indiana data is similar.
How Radon Testing Works
There are two main types of tests:
Short-term test (48–96 hours), The standard test used during real estate transactions. A continuous radon monitor sits in the lowest livable level of the home (usually the basement) and takes hourly readings. We use professional-grade monitors that track temperature, humidity, barometric pressure, and tamper detection. After the test period, we collect the device and provide a report with the average concentration in pCi/L.
Long-term test (90+ days), Better for understanding annual exposure since radon levels naturally fluctuate with weather and season. This is what we recommend for homeowners who already live in the property and want a more accurate picture of long-term exposure.
What the Results Mean
- Below 2.0 pCi/L, Low. No action required, though periodic re-testing is wise.
- 2.0 – 4.0 pCi/L, Elevated. Mitigation is recommended but not required by EPA.
- Above 4.0 pCi/L, The EPA action level. Mitigation is strongly recommended.
If your home tests high, there's good news: radon mitigation is well-understood and effective. A licensed mitigation contractor installs a sub-slab depressurization system that vents radon from beneath the foundation to the outside, typically reducing levels by 90% or more. Mitigation costs usually run $1,200–$2,500 in the Chicagoland area.
When to Test
Test radon in your home if:
- You've never tested before
- You're buying or selling a home (mortgage lenders increasingly require it)
- You've finished a basement that didn't previously have living space
- It's been more than two years since the last test
- You've done significant renovations or foundation work
Why Test Even in New Homes
A common misconception is that new construction is radon-safe. It isn't. New homes can have radon levels just as high, sometimes higher, because they're sealed more tightly than older homes. The only way to know is to test.
Schedule Radon Testing
Gold Coast Home Services performs professional radon testing across Illinois and Indiana using continuous radon monitors with tamper detection. We can add a test to your home inspection or schedule it as a standalone service.
Reach out at (312) 358-1200 or tonyldiggs@gmail.com to set up a test.