Radon Mitigation in O’Fallon, MO

A radon mitigation system in O’Fallon, MO is a sealed pipe and a continuously running fan that pull radon from under the house and release it outdoors, bringing the home below the EPA action level of 4.0 pCi/L. Air Sense Environmental, IEMA-licensed (#RNM20232346) and NRPP-certified, designs each O’Fallon system around the foundation in front of it.

Does a O’Fallon home need radon mitigation?

The trigger is the test result: at or above 4.0 pCi/L the EPA recommends fixing a O’Fallon home, and between 2 and 4 pCi/L it suggests considering it. St. Charles County is in EPA Radon Zone 2, where the predicted average indoor radon level is 2 to 4 pCi/L, and individual O’Fallon homes routinely test well above the 4.0 pCi/L action level. Missouri’s Department of Health and Senior Services reports that roughly one in three homes tested through its statewide program between 2003 and 2023 came back at or above 4.0 pCi/L.

O’Fallon is the largest suburb of St. Louis, with more than 90,000 residents, and most of its housing went up between the 1990s and 2010s on poured basements set into St. Charles County’s silty clay soils. If the home has not been tested yet, start with radon testing in O’Fallon.

Which radon mitigation system fits a O’Fallon home?

The system follows the foundation:

• Basement slab: sub-slab depressurization, the most common system in O’Fallon
• Crawl space: sub-membrane depressurization under a sealed vapor barrier
• Sump pit: a sealed sump lid tied into the system, covered in the sump pump radon mitigation guide
• Slab-on-grade: a suction point routed through a garage, closet or exterior wall
• Mixed foundations: multiple suction points balanced on one fan

The O’Fallon homes Air Sense Environmental mitigates most often:

• 1990s and 2000s subdivision homes on poured basements along Highway K and Highway N
• Homes in the older core near Main Street and the original town
• Walkout-basement homes on the sloped lots toward Dardenne Prairie
• Newer slab-on-grade villas and townhomes near Interstate 64

How is a radon mitigation system installed in O’Fallon?

1. Assessment and diagnostics. The foundation, sump, cracks and pipe route are checked during a free in-home estimate.
2. Suction point. A core hole through the slab, or a sealed membrane in a crawl space, gives the fan something to pull from.
3. Pipe and fan. PVC pipe runs to a fan mounted outside the living space, in the attic, garage or on an exterior wall, and vents above the roofline.
4. Sealing. Cracks, the sump lid and other openings are sealed so the fan can hold suction.
5. Manometer and verification. A U-tube manometer shows the system is running, and a post-mitigation test proves the result.

Most O’Fallon installations are completed in a single day. The full walk-through is on the radon mitigation system installation page.

How much does radon mitigation cost in O’Fallon, MO?

Foundation type, suction points and fan size set the price of a O’Fallon system, which is why quotes follow a free in-home assessment. The St. Louis radon mitigation cost guide lists the current ranges by system type.

How do you know the radon mitigation system worked?

A post-mitigation radon test is the only proof. Air Sense Environmental includes it, designs O’Fallon systems to a target well below the 4.0 pCi/L action level, and recommends retesting every two years. When a fan eventually wears out, radon fan replacement restores the system.

O’Fallon neighborhoods and nearby communities

Air Sense Environmental works across O’Fallon, MO, including the Highway K corridor, the original town along Main Street and the neighborhoods toward Dardenne Prairie, in ZIP codes 63366 and 63368. Nearby communities with their own service pages:

• Radon mitigation and testing in St. Peters, MO
• Radon mitigation and testing in St. Charles, MO
• Radon mitigation and testing in Wentzville, MO
• All Air Sense Environmental service areas

From Our Work