How to Lower Radon Levels in a Kansas City Home

So your test came back high. That is the moment most Kansas City homeowners call me, and the first thing they ask is what they can do themselves to bring the number down. I will give you the honest version. A few things help a little, one thing fixes it, and a couple of popular ideas do almost nothing. Here is how it actually breaks down.

First, confirm the reading is real

Before you spend a dollar, make sure the number is trustworthy. Radon swings day to day with weather and how the house is running, so a single short test that lands just over the 4 pCi/L action level is worth confirming. If your first result was a two-day charcoal kit, a follow-up test or a continuous monitor gives you a steadier picture. If you are already well above the action level, you do not need to keep retesting, you need to plan a fix. Either way, knowing your real baseline is what every other decision hangs on.

What helps a little, and what does not

People love the idea of a free fix, so let me be straight about the small stuff. Sealing visible cracks in the slab, caulking around plumbing penetrations, and covering an open sump pit can trim your number a bit and they are worth doing, but on their own they rarely bring a high reading below the action level and they do not last. Opening windows drops radon while they are open and it climbs right back the moment you close up for the winter, which is exactly when levels here are highest. Houseplants, air purifiers, and tabletop ionizers do essentially nothing for radon. Do not spend money there.

The fix that actually works

The reliable answer is a mitigation system, and the standard for our slab-and-basement homes is active sub-slab depressurization. In plain terms, a pipe is set into the ground under your foundation and a quiet inline fan pulls the radon-laden soil gas up through that pipe and vents it above the roofline before it can enter your living space. Because the fan keeps the area under the slab at slightly lower pressure than the house, the gas has nowhere to go but out. A properly installed system routinely takes a home from well above the action level down to a low, safe reading, and it keeps working around the clock. You can see how the parts fit together on our radon mitigation system page.

What to expect after it is installed

A typical KC install takes a few hours, not days. Once the fan is running you should retest to confirm the drop, and I always tell folks to test again every couple of years and after any major foundation or basement work. The fan itself is low-wattage and runs continuously, and the u-tube pressure gauge on the pipe lets you glance and confirm it is still pulling. If you ever see that gauge go flat, the fan likely needs replacing, which is a quick swap. Start with a radon test if you have not measured yet.

Frequently asked questions