Radon mitigation systems
A properly installed system keeps radon from getting in. Here's how sub-slab depressurization works and what Iowa's rules expect.
Most radon systems in Siouxland homes use sub-slab depressurization. It doesn't scrub radon out of the air. It lowers the pressure in the soil under the slab so the gas goes up a pipe and out above the roof instead of through your floor.
What does an installer put in?
- A core hole through the basement slab, with a small pit dug underneath.
- PVC pipe from the pit, run up through a closet, chase or garage to the attic, or out the rim joist and up an exterior wall.
- A radon fan in the attic, garage or outdoors, running continuously.
- A discharge above the roof edge, kept away from windows, doors and other openings.
- Sealing of major cracks, accessible floor-wall joints and the sump pit with an airtight lid.
- A U-tube manometer or other gauge so you can see the fan is pulling.
What do Iowa's 2026 rules require?
Iowa HHS adopted a rewritten radon mitigation chapter that took effect July 1, 2026. Among its requirements:
- Anyone mitigating for a fee must hold an Iowa HHS credential.
- The building is tested before and after mitigation, unless the owner waives it on the department's form.
- The post-mitigation test starts at least one day after the work is finished and within 30 days of installation.
- Those tests are done by a measurement specialist from a different firm than the mitigator, or by the homeowner or occupant.
- The system must reduce radon below 4 pCi/L in the area or level where it's installed.
Walkouts, split levels and additions
Sioux City's hills mean many walkout basements, split-level homes and additions on separate footings. If air doesn't move freely between sections under the slab, the installer may add a second suction point. Ask how they'll check that the whole foundation is covered.
Inside or outside pipe?
Interior pipe through a closet or garage up to the attic is hidden and protected from cold. Exterior runs are simpler but visible, and in a winter where the average January temperature is about 20 degrees, condensation in outdoor pipe has to drain instead of freezing.
What affects the price?
- Foundation size, type and number of sections
- Soil and fill under the slab
- Pipe route and fan location
- Extras such as sump lids, sealing or a crawl space membrane
The radon company prices the job after it understands your foundation, usually after a visit. We don't quote prices, and a number over the phone is only a ballpark, not a written bid.
Where we connect you with help
Common questions
Does the fan run constantly?
Yes. Radon fans are designed to run all the time. Check the gauge now and then to be sure it's still working.
Will sealing cracks alone fix radon?
Usually not. Sealing helps a system work better, but by itself it rarely lowers radon enough.
Related services
More background: Siouxland radon guide.
Radon number higher than you hoped?
Call and a local radon mitigation company will look at the house and quote a system.