A mitigation system is mechanical, and mechanical things age. The fan runs continuously from the day it is installed, which is what makes it effective and also what puts it on a clock. Fans have a service life and eventually need replacement. Seals age. Pipes get bumped during other work. None of this is dramatic, but it does mean a system installed years ago and never looked at since is a system nobody has confirmed lately.
The homeowner's only readout is usually the small gauge mounted on the pipe, and the most common failure story is not a catastrophe but simple inattention: the fan quietly stops, nothing changes that anyone can hear or smell, and months pass. Knowing what the gauge should look like, glancing at it now and then, and re-testing periodically is the whole maintenance routine. It is a short list, and it is the difference between owning a system and owning a pipe.
You can do this yourself in a few seconds. Note what the gauge reads and whether it matches what was recorded at installation. A change in that reading is the flag that prompts a call.
A contractor traces the system end to end: suction point, pipe run, fan, discharge, seals and electrical. The point is to find what has changed since installation rather than to redesign anything.
Usually this means a fan replacement, a reseal, or fixing something a different trade disturbed. The existing pipe route is normally reused, which keeps the work small.
A test after service closes the loop. Keep that result with the installation paperwork so the system has a history, which also matters whenever the house is sold.
Service pricing turns on how much of the existing system can stay. A fan swap that reuses the existing pipe run is the small end. Access drives it next: a fan mounted where someone can reach it easily is a different visit than one in an awkward attic or high on an exterior wall. Fan sizing follows the original design and the conditions under the slab. House footprint and foundation type still matter when the visit turns into added suction or crawl space work, and whether the existing sump or drain tile is part of the path affects the approach. A retest is quoted separately, and it is worth including.
Periodically, and any time something changes. That includes after a fan replacement or any service work, after work that alters the foundation or the way the house handles air, and after a long stretch with no measurement at all. Levels move with season and how a house is operated, so a system verified once years ago has not been verified recently. A test is the only thing that closes that gap.
Check the gauge on the pipe. Its reading changes when the fan is no longer pulling, and that is the entire early warning system, because a stopped fan makes no smell, no sound and no visible difference indoors. Learn what your normal reading looks like when the system is healthy. Some systems also have an alarm, which is a worthwhile addition if yours does not.
Usually, yes. The pipe route, suction point and sealing are the substantial parts of the installation, and they normally stay. A replacement fan is matched to the original sizing and the conditions under the slab, then the system is restarted and the gauge confirmed. Retesting afterward is what tells you the replacement actually restored performance rather than just restarted the noise.
Start with a test, because that tells you where you stand today regardless of what the file does or does not contain. Then have the system inspected so you know what you own: where the suction point is, how the pipe is routed, how old the fan appears to be and whether the discharge is correct. From there you have a baseline and a maintenance history that begins with you.
Everything begins with a measurement. A contractor places a short-term device for a quick reading or a long-term device for a closer look at your yearly average, then hands you a number you can make a decision from.
Learn more →When a reading sits at or above the action level the EPA publishes, the standard remedy is sub-slab depressurization: a sealed pipe and a fan that draw soil gas from beneath the slab and vent it above the roofline.
Learn more →A sale runs on its own clock. Radon tests during a transaction carry timing rules and closed-house requirements, and it saves friction to settle early who orders the test and who deals with the result.
Learn more →During a build, the pipe can be run before the drywall closes the walls. A passive rough-in is far simpler than routing a system through a finished house, and adding a fan later is a small job.
Learn more →County, foundation type, and whether a deadline is involved is enough to start.