A radon mitigation system is a set of parts that pulls soil gas from under your home and sends it outside before it can build up indoors. Knowing the parts makes a quote easier to read and helps you spot a system that isn't working. This page walks through each part using EPA's homeowner guide and Iowa's mitigation rule.
Active or passive
Iowa's rule defines an active system as one that reduces radon with an in-line fan [1]. A passive system has no fan. It relies on air rising in a vertical vent pipe that runs through heated space from the suction pit to 12 inches above the roof [1]. EPA says passive subslab suction is usually tied to radon-resistant features in new homes and generally doesn't lower high levels as well as an active system [2]. Turning a passive system into an active one, or a "radon system modification" such as adding or moving pipe, fans or suction points, has to be done by a person credentialed under the rule. Swapping a part for an equivalent one that doesn't change how the system works or its layout isn't a modification [1].
The parts
| Part | What it does |
|---|---|
| Suction point | A hole through the slab, a capped sump, or a sheet over a crawl space floor where suction is applied [2] |
| Vent pipe | Carries soil gas up and out; EPA's builder page describes 3- or 4-inch Schedule 40 PVC labeled "Radon System" [3] |
| Fan | Creates the suction; EPA says it must not sit in or below a livable area [2] |
| Warning device | Usually a manometer, a small gauge that shows whether the system has suction [2] |
| Labels | EPA says systems must be clearly labeled so no one changes them by accident [2] |
Where the exhaust goes
EPA's guide says the exhaust of a soil suction system must vent above the roof surface and at least 10 feet above the ground. It must also be at least 10 feet from windows, doors or other openings unless it vents at least 2 feet above them [2]. If a quote shows the pipe ending at the side of the house near a window, ask why.
What you should get at the end
Iowa's rule says the operation, maintenance and monitoring package a credentialed specialist gives the owner must include the phone number for the Iowa radon program [1]. The rule also requires the specialist to keep records for each system, including a description, the materials used, diagnostic results and the cost [1]. Keep your own copy of the contract and the post-mitigation test.
Living with it
EPA says fan systems slightly raise your electric bill, that the fan must run all the time, and that you should retest at least every two years [2]. HomeGuide compares the fan's power draw to a 60-watt light bulb, or about $70 to $80 a year [4]. See radon fan replacement for when the fan wears out, and radon mitigation cost for install prices.
FAQ
Why does the gauge matter?
It's the quickest way to see that the fan is still pulling. EPA says to look at it on a regular basis [2].
Can the fan go in my basement?
EPA says the exhaust fan must not be located in or below a livable area [2].
Get a quote
Ask for a quote on a system and say whether you have a basement, slab or crawl space.
We're a referral service, not a contractor. We send mitigation requests only to contractors on Iowa HHS's current credentialed list and testing requests only to state-certified radon measurement specialists, but we don't otherwise vet them, a referral is not an endorsement, and independent contractors may pay us for referrals.
Sources
- Iowa Administrative Code 641, Chapter 44, Radon Mitigation (ARC 0290D, IAB 5/13/26, effective 7/1/26). https://www.legis.iowa.gov/docs/iac/chapter/641.44.pdf
- U.S. EPA, Consumer's Guide to Radon Reduction, EPA 402/K-10/005 (2025 edition, PDF). https://www.epa.gov/sites/default/files/2016-12/documents/2016_consumers_guide_to_radon_reduction.pdf
- U.S. EPA, Radon-Resistant Construction Basics and Techniques, last updated Aug 6, 2026. https://www.epa.gov/radon/radon-resistant-construction-basics-and-techniques
- HomeGuide, "How Much Does a Radon Mitigation System Cost? (2026)," Kristen Cramer, Feb 5, 2026. https://homeguide.com/costs/radon-mitigation-cost