If a radon test in your St. Charles home came back high, or if your property sits on ground where radon is common, the next question is how to reduce it. A radon mitigation system is the usual answer. This checklist covers what a homeowner can check and ask about before, during, and after installation. It does not replace an assessment by a qualified professional.
What the system does
Radon is a naturally occurring gas that moves up through soil and rock and can collect in basements and crawl spaces. A common design is a sub-slab depressurization system. A pipe is set into the soil or gravel beneath the slab, and a fan draws the gas from below the house and vents it outside, above the roofline. The goal is to keep the gas from entering the living space. The system works by changing air pressure under the floor, so the way it is built matters as much as the fan.
Before the work starts
- Ask for a written plan that shows where the suction pipe goes, where the fan sits, and where the exhaust ends.
- Confirm which test was used to decide the system is needed, and whether a follow-up test is included.
- Ask whether the home has a sump pit or floor drain, since open pits affect suction and need to be sealed or covered as part of the design.
- Check whether the home has a crawl space. Crawl space systems are designed differently from slab systems.
- Ask how the work will affect finished areas such as drywall, flooring, and finished basement rooms.
Things to look at during installation
You do not need to be an expert to notice basic issues. Walk through the house while the work is underway and look at the following.
- Pipe routing. The vertical run should be neat, supported, and sealed where it passes through the building envelope.
- Exhaust location. The pipe should discharge above the roofline and away from windows, doors, and air intakes for gas appliances or dryer vents. Ask where the outlet will point.
- Fan placement. Fans are often installed in an unheated attic or garage space, so ask about noise and about how cold weather affects the pipe.
- Sealing. Cracks in the slab, gaps around pipes, and open sump lids should be addressed. Ask what sealant is used and how it is applied.
Reading the gauge
Most systems include a small pressure gauge, often a U-shaped tube with colored liquid, mounted on the vertical pipe. The gauge shows whether the fan is creating suction under the slab. Learn what a normal reading looks like for your system, as described in the installer's documentation, and write it on a card near the gauge. If the liquid levels move toward equal or the reading drops, check the fan, the power supply, and the seals before calling for service.
After the system is running
- Retest the air after the system has run for a while. Use a test kit or a professional test that follows the manufacturer's instructions, and compare the result with your earlier test.
- Keep the fan running continuously. Switching it off defeats its purpose.
- Check the gauge each month and after storms or power outages.
- Keep a written record with dates, test results, and any service visits.
Private wells in the St. Charles area
Homes with private wells can have a separate question. Radon can dissolve into groundwater and release into shower air, so a well owner may need water testing as well as air testing. Ask your testing provider how they handle water samples and whether they recommend a treatment step. Most St. Charles tap water comes from a public system, so this section applies mainly to homes on wells.
Keep the decision practical
A mitigation system is a home improvement that depends on correct installation and regular checks. Get the plan in writing, learn to read the gauge, retest after the work, and keep records. If the work seems rushed, if no one explains the venting path, or if the pipe is left open or unsealed, ask questions before you accept the job as finished. This checklist is a plain starting point for a St. Charles homeowner, not a promise of any particular result.