If you own a home in St. Louis and you have a radon mitigation system already installed, you might think the hard part is over. And in many ways, it is. But like any mechanical system in a house, a radon mitigation system can develop problems over time. Fans wear out, pipes get knocked loose, and the sealants that keep everything airtight can degrade. When that happens, you are looking at a need for radon system repair. It is not a crisis if you catch it early, but ignoring the warning signs can allow radon gas to creep back into your living space.
I have been working with these systems for years, and I can tell you that most homeowners do not realize something is wrong until they test again or notice their manometer reading looks off. That little gauge on the pipe is your first line of defense. If it shows zero or near-zero pressure, your system is not pulling air the way it should. That is the moment to call a professional who specializes in radon mitigation system maintenance and repair.
Why Radon Systems Fail
Radon mitigation systems are simple by design, but they live in harsh conditions. The fan sits in the attic or outside on the wall, exposed to temperature swings, moisture, and dust. Over time, bearings dry out and the motor can seize. That is the most common failure point I see. A radon fan that runs constantly for five to seven years is doing its job, but it will eventually need replacement.
Another frequent issue is damage to the PVC piping. Someone bumps into it in the garage, a lawnmower kicks up a rock, or a critter chews through an exposed section. Even a small crack in the pipe can break the vacuum and let radon gas escape before it reaches the fan. The same goes for the sealant around the suction point and the floor penetrations. If that seal cracks, you lose the negative pressure that keeps the sub-slab depressurization working.
Less common but still real: electrical problems. A tripped breaker, a loose wire, or a failed capacitor in the fan motor can stop everything. A quick diagnostic test by a technician can pinpoint whether the issue is electrical or mechanical. Many times, it is just a simple fix like reseating a connection, but sometimes it means a full fan replacement.
Signs Your System Needs Attention
You do not need to be a radon expert to spot trouble. Here are the things I tell homeowners to watch for:
- The manometer reads zero or has fluid that is not level. This means no pressure difference is being created.
- Strange noises from the radon fan, like grinding, buzzing, or a rattle that was not there before.
- Dust or debris around the fan housing or pipe joints, which can indicate a leak.
- A radon test result that is higher than it was after the system was first installed. This is the most definitive sign that something is off.
- Water pooling inside the PVC piping or at the suction point, which can block airflow.
If you see any of these, do not assume the system has stopped working completely. Sometimes the fan is still running but not pulling enough air, or a partial blockage is reducing efficiency. A proper system inspection by a trained technician will identify the root cause and tell you whether you need radon system repair or just a minor adjustment.
The Repair Process: What to Expect
When a technician arrives to look at your system, the first thing they will do is check the manometer and listen to the fan. If the fan is dead, they will replace it with a compatible unit. Brands like RadonAway are common in this area, and the technician will match the replacement to your system's specifications. Fan replacement is the most frequent repair, and it is usually straightforward, assuming the existing wiring and mounting are in good shape.
If the problem is a leak in the PVC piping, the technician will locate it using a smoke test or by pressurizing the system and listening for hissing sounds. Small leaks can be sealed with a high-quality sealant. Larger damage may require cutting out the damaged section and coupling in a new piece of pipe. The same approach applies to the suction point if the seal around it has failed.
Sometimes the issue is not a leak or a dead fan but a system that was undersized or poorly designed from the start. In those cases, radon system repair might involve a system upgrade, like adding a second suction point or replacing an undersized fan with a more powerful model. This is less common, but I have seen it in older homes where the original installer cut corners.
Preventive Maintenance Is Worth It
I am a big believer in corrective maintenance, but I would rather see homeowners avoid the problem entirely. A yearly inspection of your radon mitigation system costs very little compared to the peace of mind it provides. During that visit, the technician will check the fan, manometer, and piping, and verify that the sub-slab depressurization is pulling correctly. They will also look for any new cracks in the slab or gaps around the suction point that could let radon gas bypass the system.
Another thing I recommend: keep the area around your system clear. Do not stack boxes against the pipe or let vegetation grow over the exhaust. And if you have a radon fan installed in the attic, make sure the attic is ventilated properly so the fan does not overheat in the summer.
If you bought your home with an existing system, ask the previous owner or the installer about the post-mitigation warranty. Many reputable companies, including Air Sense Environmental, offer a warranty on parts and labor for the first few years. That warranty often covers fan replacement and other mechanical failures, so you may not have to pay out of pocket for the repair.
When to Call a Pro
I have talked to homeowners who tried to fix their radon system themselves. It rarely ends well. The tools and materials are not exotic, but the diagnostics take experience. A manometer reading that looks normal can still mask a partial failure. And if you reseal a pipe joint but miss a small crack elsewhere, you have not solved the problem. Worse, you might think you did, and that false confidence can let radon gas accumulate for months before you test again.
A professional, on the other hand, will run a full diagnostic test after any repair to confirm the system is back to spec. They will measure the negative pressure at the suction point, check the flow rate, and verify that the system is venting properly above the roofline. They will also look at the SaniDuct or any other components that might need attention. That thoroughness is what separates a temporary patch from a real fix.
In St. Louis, radon levels vary from neighborhood to neighborhood, but the EPA still recommends testing every two years even if you have a system. Radon gas is colorless and odorless, so you cannot rely on your senses to tell you the system is working. You have to rely on the equipment and on regular checks.
Final Thoughts
Owning a radon mitigation system is a smart move, but it is not a set-it-and-forget-it solution. Like your furnace or your water heater, it needs occasional attention. Fan replacement, sealant touch-ups, and pipe repairs are all part of the normal lifecycle of these systems. The key is to stay ahead of problems before they turn into a full system failure that leaves your home unprotected. If you see a red flag on your manometer or hear a funny noise from your radon fan, do not wait. A timely radon system repair is a small price to keep your indoor air safe.