# New Construction Radon Systems | Radon Mitigation Des Moines > Passive radon systems for new Iowa homes under HF 2297, sub-slab prep and sealing, post-construction testing and passive-to-active fan activation. URL: https://radonmitigationdesmoines.com/new-construction-radon-systems/ New construction # New Construction Radon Systems We rough in passive systems for builders, test after move-in and upgrade passive pipes to active. Request An Estimate [/free-estimate/ →](/free-estimate/) Call Now To Book [tel:+15152187447 →](tel:+15152187447) Last updated October 27, 2026 · Pricing: Builder and homeowner quotes on request. ![New construction home in a Des Moines suburb with a radon pipe stub set before the slab pour](/images/misc/new-construction-home-framing-in-a-waukee-subdivis.webp) - Certified Radon Techs - 5-Year Warranty - 24/7 Support Know the risk ## Why New Homes in the Des Moines Suburbs Still Test High From Waukee to Ankeny, new homes go up fast. These are the radon gaps we see on job sites and after move-in. - 01 ### Radon-ready homes that test high A passive pipe relies on natural draft. In many Iowa homes that is not enough to get below 4.0 pCi/L. - 02 ### HF 2297 on every start Since July 1, 2026, new single-family homes and duplexes need a passive system. Builders need it right every time. - 03 ### Details that fail under the slab Missing aggregate, open retarder seams and unsealed penetrations weaken a passive system before the pour. - 04 ### Radon work slowing the pour Pour dates move with the weather. We fit radon prep between plumbing rough-in and the pour. What it is ## What Is New Construction Radon Systems? Since July 1, 2026, Iowa House File 2297 requires passive radon systems in new single-family homes and duplexes. Building radon resistance into a home while the slab is open costs far less than retrofitting it later, and it gives the homeowner an easy path to an active system if they ever need one. For builders, we handle the parts that are easy to get wrong. That means a layer of gas-permeable aggregate under the slab, a sub-slab T-fitting or perforated loop, a polyethylene soil-gas retarder lapped and sealed at the seams, sealed slab penetrations, and a passive vent stack that runs straight up through the conditioned space to the roof. We follow radon-resistant new construction (RRNC) practice from IRC Appendix F and the ANSI/AARST CCAH standard. For homeowners, a passive pipe is a head start, not a guarantee. A passive soil depressurization system relies on natural draft, and in many Iowa homes that isn't enough to get below 4.0 pCi/L. We test after move-in. If the level is still high, we activate the pipe by adding a fan in the attic, a dedicated attic junction box and a U-tube manometer. It's usually a short visit. Every passive install, activation and test is done by Iowa HHS-credentialed technicians. Activations and installs are covered by our 5-year warranty, and we work around pour dates so radon work doesn't slow down your build. - Sub-slab preparation & sealing - Passive mitigation system installation - Post-construction testing and upgrade ![Soil-gas retarder being laid over gravel in a new basement before the slab pour](/images/features/heavy-polyethylene-soil-gas-retarder-being-rolled-.webp) WHAT'S INCLUDED - Sub-slab preparation and sealing - Passive radon system installation - Post-construction radon testing - Passive-to-active fan activation - Attic fan mounting, electrical and manometer - Builder scheduling around pour dates ## For Builders: Getting Passive Systems Right Wondering what the new rule means for your next pour? Here’s the short version for new construction radon systems. Iowa HF 2297 made passive radon systems standard in new single-family homes and duplexes as of July 1, 2026. The rule is simple. The details under the slab are where systems work or fail. According to Iowa HHS, the state code points to the passive methods in Appendix AF of the 2021 International Residential Code. Before the change, 11 jurisdictions already required them, including Polk County and Altoona. Crews in those areas know the routine. A June 30, 2026 construction law update added one caution. The Iowa Department of Inspections, Appeals, and Licensing (DIAL) issued enforcement guidance on June 25, and the code amendment itself was still being finalized. Check with your local building department before you lock in plans. | Component | What it does | Common mistake we avoid | | --- | --- | --- | | Gas-permeable aggregate | Lets soil gas move freely to the collection point | Fines or sand mixed into the gravel layer | | Sub-slab T-fitting or perforated loop | Collects soil gas under the slab | Fitting crushed or buried in fines during the pour | | Polyethylene soil-gas retarder | Blocks gas from rising through the slab | Unlapped seams and torn sheeting around plumbing | | Sealed penetrations and joints | Closes the easy entry paths | Open gaps at plumbing stubs and sump basins | | Passive vent stack | Carries soil gas up and out through the roof | Pipe routed through unconditioned space or with long horizontal runs | | Attic junction box | Makes future fan activation fast and safe | No power left near the pipe in the attic | Radon-resistant guidance from the Connecticut Department of Public Health lists the same basics: - At least 4 inches of clean gravel with no fines - 6 mil polyethylene sheeting between the gravel and the slab - A vent pipe of at least 3-inch PVC running from the sub-slab gravel to the roof - Room and a power source in the attic for a future fan Here’s a pro tip on the sheeting. A Connecticut radon fact sheet from SOS Radon calls for 12-inch overlaps at seams, sealed with tape. That one step fixes the unlapped seams we see most often. We work with builders across Polk and Dallas counties, from Waukee and Grimes to Ankeny and Altoona. Tell us your pour schedule and we’ll fit the work in around it. ## For Homeowners: Should You Activate Your Passive Pipe? If your home was built with a passive pipe, start with a test. A 48-hour continuous radon monitor test in the lowest lived-in level tells you where you stand. The EPA recommends fixing a home at 4.0 pCi/L or higher and considering action between 2.0 and 4.0. Here’s how we read the results for a home with a passive pipe: - **Below 2.0 pCi/L:** The passive system may be doing its job. Retest every two years. - **2.0 to 3.9 pCi/L:** Consider activating, especially if you plan to finish the basement. - **4.0 pCi/L and above:** Activation is recommended. It’s usually the fastest, simplest fix since the pipe is already there. ![Radon fan installed on a passive pipe in an attic](/images/content/newly-installed-radon-fan-on-the-passive-vent-pipe.webp) Many owners in growing suburbs like Waukee, Ankeny and the Easter Lake area assume a new home is radon proof. Testing is how you know. Polk County’s health department reports that more than 70% of Iowa homes test above the EPA action level of 4.0 pCi/L. Our guide on how often to test for radon [/guide/how-often-to-test-for-radon/ →](/guide/how-often-to-test-for-radon/) covers when to retest after you move in. > **Why passive isn’t always enough** > > A passive stack depends on warm air rising in the pipe. On mild days, or when soil under the slab is tight, that draft is weak. An attic fan creates steady suction no matter the weather. The gap can be big. One radon industry guide from Erase Radon puts passive systems at a 30% to 50% reduction, compared with 95% or more once a fan is running. If your test lands near or above 4.0, that difference matters. ## What Activation Involves Activation turns a passive pipe into an active soil depressurization system. We: 1. Confirm the pipe is continuous from the slab to the roof and check for leaks. 2. Install a radon fan in the attic on the existing pipe. 3. Connect it to the attic junction box or add a dedicated circuit if one wasn’t left. 4. Add a U-tube manometer in a visible spot so you can check suction any time. 5. Run a post-mitigation test after the fan has run at least 24 hours. Most activations are finished in a short visit. Because the pipe is already in place, a 2026 cost guide from InspectandTest says homes like yours often need only the fan and electrical work, typically $400 to $800. Fans do wear out. Angi says most last five to 10 years, so jot down the install date and glance at the manometer now and then. If testing shows a second slab section, like a slab-on-grade addition, needs its own suction point, we’ll explain why and quote it before doing the work. ## Builder or Homeowner, Start Here The EPA and CDC estimate radon causes more than 21,000 lung cancer deaths in the US each year. Whether you’re planning new construction radon systems or living with a passive pipe today, a little action now pays off. Builders can request a quote [/contact/ →](/contact/) with plans and the pour schedule. Homeowners can book a radon test [/radon-testing/ →](/radon-testing/) or send us an existing result. If the result is high, see how our residential radon mitigation [/residential-radon-mitigation/ →](/residential-radon-mitigation/) team handles homes that need more than a single fan. New to radon? Our homepage [/ →](/) covers testing, systems and the warranty in one place. Why choose us ## Why Choose Radon Mitigation Des Moines for New Construction Radon Systems? 01 ### Builder-friendly scheduling We coordinate with your superintendent around excavation, plumbing rough-in and pour dates. 02 ### Done right under the slab Aggregate, retarder seams and penetrations are where passive systems fail. We get those details right. 03 ### Fast activations Most passive-to-active upgrades take one short visit, since the pipe is already in place. 04 ### 5-year warranty Passive installs and fan activations are covered by our 5-year warranty on systems and installs. How it works ## How Does New Construction Radon Systems Work? 1. 1 ### Pre-pour prep Gas-permeable aggregate, a sub-slab T-fitting and a sealed soil-gas retarder go in before concrete. ![Finished radon mitigation system with white PVC pipe on the side of a home](/images/features/finished-radon-mitigation-system-with-white-pvc-pi.webp) 2. 2 ### Seal and vent Slab penetrations and joints are sealed, and the passive stack runs through conditioned space to the roof. ![Continuous radon monitor on a small table in a Des Moines home](/images/misc/continuous-radon-monitor-sitting-on-a-small-table-.webp) 3. 3 ### Post-construction test After move-in, a 48-hour continuous radon monitor test shows whether the passive pipe is enough. ![Printed radon test report with hourly chart on a kitchen counter](/images/misc/radon-test-report-printout-with-hourly-chart-and-a.webp) 4. 4 ### Activate if needed If the level is 4.0 pCi/L or higher, we add an attic fan, junction box and manometer, then retest. ![U-tube manometer on a radon pipe showing steady suction](/images/misc/close-up-of-a-u-tube-manometer-on-a-white-radon-pi.webp) Request An Estimate [/free-estimate/ →](/free-estimate/) Our work ## New Construction and Activation Work Installs and tests across the Des Moines metro. Click a photo to enlarge. Reviews ## What Customers Say About Our New Construction Radon Systems ★★★★★ > "Our new build in Waukee came with a passive pipe but still tested above 4. They added the attic fan and manometer in one visit and explained the readings." Chris L. · Waukee ★★★★★ > "They showed up the day before our pour, set the stub and retarder, and were gone by lunch. No delays, no callbacks." Site Superintendent · Ankeny builder ★★★★★ > "We assumed our Altoona home was radon proof because of the pipe. The test said otherwise. The fan went in quickly and the retest came back low." Priya D. · Altoona Read our reviews on Google → [https://www.google.com/maps?cid=14625480479653910645 →](https://www.google.com/maps?cid=14625480479653910645) FAQ ## New Construction Radon Systems Questions, Answered ### Not always. Iowa HF 2297 requires passive systems in new homes, but a passive pipe doesn't guarantee a level below 4.0 pCi/L. Test after move-in. If it's still high, we activate the pipe with an attic fan and manometer. ### Starting July 1, 2026, newly built single-family homes and duplexes in Iowa must include a passive radon mitigation system installed during construction. ### It's a sealed vent pipe from a gravel layer under the slab up through the roof. Warm air in the pipe creates a natural draft that pulls some soil gas out. It has no fan until it's activated. ### We cut in a radon fan on the pipe in the attic, wire it to a dedicated junction box, add a U-tube manometer you can see, and retest after the fan has run at least 24 hours. ### Test after you've moved in and the heating or cooling system is running normally. A 48-hour continuous radon monitor test gives a fast answer. ### Anyone mitigating radon for pay in Iowa must hold an Iowa HHS credential. Using a credentialed team also helps make sure the system works if the homeowner later activates it. ### Yes. We schedule radon prep between plumbing rough-in and the slab pour, and we can turn around quickly when weather moves your dates. ### Yes. Fan activations and new installs carry our 5-year warranty on systems and installs. Still have a question? Our support line answers 24 hours a day, 7 days a week. Request An Estimate [/free-estimate/ →](/free-estimate/) Call Now To Book [tel:+15152187447 →](tel:+15152187447) More services ## Related Services SERVICERadon TestingWe run CRM, short-term, long-term, real estate and post-mitigation tests with credentialed testers.Learn more → [/radon-testing/ →](/radon-testing/) SERVICEResidential Radon MitigationWe size the system to your foundation: basement sub-slab, crawlspace, exterior or vapor intrusion.Learn more → [/residential-radon-mitigation/ →](/residential-radon-mitigation/) SERVICERadon System MaintenanceWe fix fan alarms, error codes, pipes and joints, and maintain and inspect radon systems from any installer.Learn more → [/radon-system-maintenance/ →](/radon-system-maintenance/) Des Moines & Central Iowa ## Ready to Book New Construction Radon Systems? Request An Estimate [/free-estimate/ →](/free-estimate/) Call Now To Book [tel:+15152187447 →](tel:+15152187447)