A radon mitigation system is not a set-it-and-forget-it appliance. The fan that pulls radon from beneath your slab runs 24 hours a day, every day, and like any motor it eventually wears out. Most inline radon fans last 5 to 10 years, and when one quits, radon levels in the house climb right back toward where they were before the system went in.
That matters more here than almost anywhere else. Iowa has the highest average indoor radon levels in the nation, roughly 7 in 10 Iowa homes test at or above the EPA action level of 4.0 pCi/L, and Johnson County sits in EPA Radon Zone 1, the highest radon potential category. A dead system in Iowa City usually means the house is back to elevated levels.
We repair and maintain radon mitigation systems throughout Iowa City, Coralville, North Liberty, Tiffin, Solon, University Heights, and the rest of Johnson County, regardless of who installed them. Our technicians are certified through the Iowa Department of Health and Human Services radon program, as Iowa law requires for radon work.
Warning Signs Your Radon System Has Failed
The clearest sign is the u-tube manometer mounted on the system pipe, usually in the basement. When the fan is running and pulling suction, the colored fluid in the two arms of the tube sits at different heights. If the fluid levels have equalized, the fan has stopped pulling. That is the most reliable failure indicator, and it takes five seconds to check.
Sound is the next tell. A healthy radon fan hums quietly and steadily, to the point that most homeowners forget it exists. Grinding, rattling, or humming that surges and fades points to failing bearings or a motor on its way out. A fan making new noises is usually months, not years, from quitting.
Ice and condensation problems show up in Iowa winters. Moisture pulled from the soil condenses inside the pipe, and a poorly routed discharge can freeze and choke the system even while the fan keeps spinning. Water gurgling in the pipe or ice at the discharge point is worth a service call.
Finally, rising retest numbers are a failure sign even when everything looks normal. If a follow-up test comes back higher than your post-mitigation result, something has changed: a tired fan, a new slab crack, a failed sump lid seal, or a remodel that opened new entry points.
How to Read Your U-Tube Manometer
The manometer is a simple U-shaped tube partly filled with colored fluid, measuring the vacuum the fan creates inside the pipe. With the fan off, both columns rest at the same height. With the fan running, suction pulls one column up and pushes the other down, and the difference between the two readings is the system pressure.
What matters most is not the exact number but the change. Your installer should have marked the normal operating level. If the fluid sits where it always has, the fan is pulling as designed. If the gap has shrunk noticeably, airflow is partially blocked, often by ice, debris, or a failing fan. If the two columns are level, the system is doing nothing.
We recommend glancing at the manometer once a month, the same way you might check a furnace filter. If you are not sure what your normal reading should be, take a photo and send it to us, and we can usually tell you over the phone whether a visit is warranted.
Radon Fan Replacement
Fan replacement is the most common repair we do. Inline radon fans typically run 5 to 10 years before bearings or motors give out, so a fan installed a decade ago is living on borrowed time. Replacement is usually a straightforward visit: we swap the fan at its couplings, verify the manometer reading, and check the discharge and seals while we are there.
The part people miss is that fans are not interchangeable. Radon fans come in different airflow and suction ratings, and the right fan depends on the soil under your slab, the size of the footprint, and how the suction point was built. Tight glacial clay soils common around Johnson County need a different fan than a house sitting on gravel fill. Swapping in whatever fan is cheapest online can leave you with a system that runs but does not actually lower radon.
When we replace a fan, we match it to the measured airflow and pressure of your existing system rather than guessing. If the original fan was undersized to begin with, we will tell you, show you the readings, and quote the correct fan so the replacement solves the problem once.
Fixing Bad Installs From Other Companies
A fair share of our repair calls turn out to be installation problems rather than worn-out equipment. Radon mitigation got busy in Iowa City after the rental ordinance took effect in July 2021, which required testing, and mitigation at 4.0 pCi/L or higher, for single-family and duplex rentals on the rental permit cycle. Some of the systems installed in that rush were done fast rather than well.
The problems we see repeatedly: fans undersized for the sub-slab conditions, so the system never developed a real pressure field; discharge pipes terminated below the eave, where exhausted radon can re-enter through windows and soffits instead of dispersing above the roofline; and sump pits left with unsealed lids, which is like running a vacuum with the hose disconnected, since the sump pit is one of the largest radon entry points in a house.
We also find suction points drilled in poor locations, unsealed floor drains and slab cracks left open near the suction point, and crawl spaces skipped entirely when they needed sub-membrane depressurization. Most bad installs can be corrected without starting over, by resealing entry points, upsizing the fan, extending the discharge above the eave, or adding a suction point. We diagnose with actual pressure and radon measurements, then fix only what needs fixing.
Annual Checkups and Retesting Schedule
The EPA recommends retesting your home every two years even with a mitigation system running. Systems degrade quietly, houses shift and crack, and remodels change how air moves through a building. A two-year retest cadence catches problems early and builds a documented history of low readings, which is worth having when you sell.
Between tests, an annual checkup keeps the mechanical side honest. We inspect the fan for noise and vibration, confirm the manometer reading against baseline, check pipe joints and the discharge point, inspect sump lid and slab seals, and look for new cracks or penetrations.
For Iowa City landlords, the rental ordinance puts radon on your permit cycle for single-family and duplex rentals, so testing is not optional. We help owners and property managers line up checkups and retests with permit renewals so the paperwork is ready when the city asks for it.
Why a Dead System Is Worse Than No System
This sounds backwards, but it holds up in practice. A homeowner with no system knows they have an open question and often tests. A homeowner with a system assumes the problem is solved for good and stops thinking about it. When the fan dies silently in year seven, the family can spend years breathing elevated radon while the pipe on the wall quietly reassures them.
Radon is the second-leading cause of lung cancer overall and the leading cause among non-smokers, and the EPA attributes about 21,000 U.S. lung cancer deaths per year to it. The risk comes from long-term exposure, which is exactly what an unnoticed failure produces. The gas comes from uranium decaying in Iowa's glacial soils, so the source never goes away.
The fix for this is boring and cheap: look at the manometer monthly, retest every two years, and replace the fan when it ages out instead of after it fails.
What a Service Visit Includes and What It Costs
A standard service visit covers the whole system, not just the complaint. We measure system pressure against design expectations, inspect and sound-check the fan, verify the discharge terminates above the eave and is clear of ice, check seals at the sump lid, floor drains, slab cracks, and pipe penetrations, and inspect any crawl-space membrane. You get a plain written summary of what we found and what, if anything, needs work.
Repairs cost a fraction of a new system. A full residential mitigation install in the Iowa City area typically runs $900 to $1,400, while a fan replacement or seal repair is well under that, and a professional retest runs about $150 to $250. If your existing system can be brought back to full performance, we repair it; we only recommend replacement when the original design cannot do the job.
If your manometer is flatlined, your fan is making noise, or you cannot remember the last time the system was checked, call us or send the form below. We serve all of Johnson County and can usually schedule a diagnostic visit within a few days.