Understanding Metro East Radon: Testing, Mitigation, and Home Safety

If you own a home in Metro East Illinois, you have probably heard about radon. But knowing it exists and understanding what it means for your house are two different things. I have spent years working with homeowners in Belleville Illinois, Edwardsville Illinois, O'Fallon Illinois, and Collinsville Illinois, and I can tell you that radon is one of those problems people tend to put off. Partly because you cannot see it, partly because the health effects take years to show up. But the reality is that radon is the second leading cause of lung cancer in the US, according to the US EPA. And in this region, the geology makes it more likely to show up in homes.

The first step is getting a handle on your own situation. That means testing. And not just once. Radon levels can shift with the seasons, with renovations, and even with changes in how you use your heating and cooling system. So if you test in the middle of summer and get a low number, that does not mean you are safe in January.

How Radon Gets Into Your Home

Radon is a radioactive gas that comes from the natural decay of uranium in soil and rock. It moves up through the ground and into the air. But when a house sits on top of that ground, the gas can seep in through cracks in the foundation, gaps around pipes, and openings around sump pumps or drains. Once inside, it can build up to levels that are dangerous over a long period of exposure.

In Metro East Illinois, the soil composition and the way many homes are built on slab foundations or with basements makes this a real concern. The Illinois Radon Awareness Act requires disclosure of known radon levels when selling a home, but many buyers still do not ask for a test until after the deal is done. By then, the new owners are living with whatever is there.

That is why I always tell homeowners: test early, test often, and use a method that gives you a reliable reading. There are several ways to do it, and each has its strengths and weaknesses.

Testing Options: From Simple to Sophisticated

The most common entry-level test is the charcoal canister. You open it, leave it in the lowest lived-in level of your home for a few days, and then mail it to a lab. It is cheap and it works well enough for a snapshot. The downside is that it only measures the average over that short window. If you happen to test during a week when the wind is high and the house is drafty, you might get a falsely low number.

A step up from that is the continuous radon monitor. This is an electronic device that sits in your home for at least 48 hours, often longer, and records radon levels hour by hour. It gives you a much better picture of the peaks and valleys. I use continuous monitors in my own work because they show me whether the level is spiking at night when the house is closed up, or staying steady through the day. That kind of detail matters when you are deciding whether mitigation is needed.

There is also a longer-term option using alpha track detectors, which you leave in place for three months to a year. Those give you the most accurate picture of your annual average exposure. For someone who is serious about knowing their risk, that is the gold standard.

When Testing Points to a Problem

The US EPA action level is 4 picocuries per liter of air. If your test comes back above that, you need to fix it. But even levels between 2 and 4 are worth addressing, especially if you have young children or elderly people in the house. The risk is cumulative, and there is no safe level of radon exposure. It is just a question of how much risk you are willing to accept.

When I consult with homeowners about metro east radon issues, the first thing I do is look at the house itself. Is there a basement? A crawl space? A slab on grade? The construction method determines which mitigation strategy will work best. And the second thing I consider is the soil type around the foundation. Clay soils, which are common in parts of Metro East Illinois, can trap radon and force it sideways into the house rather than letting it dissipate upward.

Mitigation: How It Works

The most effective and widely used method is sub-slab depressurization. This involves drilling a small hole through the basement floor or slab, creating a suction point underneath the concrete, and then running a pipe from that hole up through the house to a radon fan mounted on the exterior wall or roof. The fan creates a vacuum that pulls the radon-laden soil gas from under the house and vents it safely above the roofline, where it dilutes in the outdoor air.

Sometimes called soil suction, this approach works because it addresses the source of the problem rather than just sealing cracks. Basement sealing alone is rarely enough. Caulking every joint and gap helps reduce the amount of radon that can enter, but gas is sneaky and will find the tiniest opening. You need active suction to truly lower the level.

The fan itself is a critical component. A good radon fan runs continuously, quietly, and uses very little electricity. It has to be sized correctly for the size of the house and the soil conditions. Too small and it will not pull enough vacuum. Too large and it can create noise issues or even pull conditioned air out of the living space, raising your heating and cooling bills.

I have seen homes in Collinsville Illinois where a single suction point dropped radon levels from 12 pCi/L down to 1.5 pCi/L. That is a dramatic change. And in a house in Edwardsville Illinois with a complicated crawl space, we had to install two suction points and seal off the crawl space from the rest of the house. It took more work, but the final reading was under 1 pCi/L.

What to Look for in a Mitigation Contractor

Not all contractors are equally skilled at radon mitigation. It is a specialized trade. You want someone who understands the physics of soil gas movement, who uses a manometer to measure pressure differences, and who can troubleshoot when the first approach does not work. A good contractor will also test after the system is installed to confirm the level has dropped. That post-mitigation test is essential. Without it, you are just guessing.

Air Sense Environmental has been doing this work in the region for years, and they follow the standards set by the NFA and HERA. Those certifications matter because they mean the installer has been trained to understand the science behind the systems, not just how to glue pipes together.

The cost of a mitigation system varies. A straightforward sub-slab job might run between $800 and $1500. A more complex house with multiple suction points or a crawl space could cost more. But when you compare that to the health risk and the peace of mind you gain, it is a small price.

Long-Term Maintenance

Once a system is installed, it needs occasional checks. The fan should run for the life of the house. If it stops, the radon levels can climb back up within days. I recommend homeowners check the manometer gauge at least once a month. It is a simple U-tube filled with colored liquid that shows whether the fan is pulling the right vacuum. If the liquid levels are equal, the fan is not working.

Also, if you make changes to the house - finishing a basement, adding an addition, or even changing the landscaping around the foundation - you should retest. Those changes can affect how the system performs.

Final Thoughts

Living in Metro East Illinois gives you access to great schools, parks, and a strong sense of community. But the geology under your feet deserves your attention. Radon is not something to panic about, but it is something to act on. Testing is easy and cheap. Mitigation, if needed, is a proven fix that will protect your family for decades.

Whether you live in Belleville Illinois, Edwardsville Illinois, O'Fallon Illinois, or Collinsville Illinois, understanding metro east radon means understanding that every house is different. The only way to know your risk is to test. And if the number is high, the technology exists to bring it down. That is the good news. You are not stuck with whatever the ground gives you.