An annual home safety audit is a practical habit — here’s how radon fits into that routine specifically.
Radon earns a fixed annual slot for a reason that sets it apart from most household hazards: there is nothing to notice. It has no smell, no colour, and no taste, it produces no symptom on the day of exposure, and the health effect it does cause takes decades to appear. Every other item on a home safety list gives you some feedback loop, however weak. A smoke alarm chirps. A leaking valve drips. Radon gives you nothing at all, which means the only signal you will ever get is the one you deliberately go and generate with a test.
- An annual check covers monitor trends, manometer readings, and retest scheduling.
- Renovations, new finished space, or unusual fan behavior should trigger an off-schedule check.
- A simple ongoing log makes future reference (and eventual resale documentation) easy.
- Building radon into an annual routine is more reliable than remembering it as a standalone task.
What to Check Annually
If you have a continuous monitor, review the past year’s trend data for any unusual spikes. If you have a mitigation system, check the manometer reading and listen for normal fan operation. Note whether you’re due for your next 2-year retest.
If you have a mitigation system, the single most informative check takes about five seconds: look at the manometer on the vent pipe. That is the small U shaped tube of coloured liquid mounted near the fan riser. When the fan is pulling, the two columns of fluid sit at different heights, and the difference is the suction the system is generating. When the columns sit level with each other, the fan has stopped. Write down the reading rather than just glancing at it, because the useful information is the comparison against last year. A reading that has drifted noticeably lower while the fan is still running usually points at a blockage, a disconnected suction point, or a fan losing performance as it ages.
Beyond the manometer, walk the visible run of the system. You are checking that the vent pipe is still sealed where it passes through the slab and the roof, that no joint has separated, that the exterior termination is clear of nesting birds, leaves, or drifted snow, and that the fan itself has not developed a bearing whine or a rattle. Then check the parts of the house that undo mitigation work: a sump lid whose gasket has perished, a floor drain that has been opened up, a new crack that has opened at the slab perimeter, and any renovation that has cut into the slab since last year. Radon mitigation depends on the slab behaving as a reasonably sealed boundary, and ordinary household changes chip away at that.
What Triggers an Off-Schedule Check
Any major renovation touching the foundation or air sealing, a new finished basement space, or noticing your mitigation fan behaving unusually (different sound, or a manometer reading that’s changed) should trigger an audit outside your normal annual schedule.
Anything that changes the pressure relationship between the soil and the house belongs on the trigger list. Adding a powerful range hood, a whole house fan, or a larger clothes dryer increases the rate at which air is pulled out of the building, and the replacement air has to come from somewhere. In a house with a slab in contact with radon bearing soil, some of it comes from below. The same logic applies in reverse to air sealing work: new windows, spray foam, or blower door directed weatherisation all reduce the incidental leakage that used to dilute indoor air, so a level that previously tested acceptable can rise without anything about the soil changing at all.
Structural and mechanical work is the other trigger category. Finishing a basement, cutting the slab for plumbing, replacing a sump pump or its lid, altering a crawlspace, adding an addition, or replacing a heating system all change either the entry paths or the pressure field. So does a significant foundation repair. And if the mitigation fan has been replaced or the system has been serviced, that is itself a reason to retest rather than assume the new fan restored the previous performance, since fans are not interchangeable across soil types and an underspecified replacement can leave part of the slab uncovered.
Keeping a Simple Record
A simple log — date, pCi/L reading, any system checks performed — kept with your other home maintenance records gives you (and eventually a future buyer) a clear history without needing to track down old paperwork years later.
A radon record is worth keeping in a form you can compare year over year, because a single number in isolation tells you very little. For each test, write down the result in picocuries per litre, the device type, whether it was short term or long term, the exact start and end dates, the room and the level of the house, and the position within that room. Placement drives the number as much as the underlying soil does, so a result recorded without its location is not comparable to anything. Add a line about the weather and whether closed house conditions were maintained, since both move the result.
For the system itself, keep the installer’s name and certification number, the installation date, the fan make and model, the number and location of suction points, and the manometer reading recorded at commissioning. That commissioning reading is the baseline every future check is measured against, and it is the number most homeowners never write down. Keep the post mitigation test result alongside it. If you ever sell the house, this file is also the documentation a buyer will ask for, and a system with a dated install record, a commissioning reading, and a history of biennial retests is a materially easier disclosure conversation than a fan of unknown age with no paperwork.
Where the Annual Audit Stops and Testing Begins
It is worth being precise about what an inspection can and cannot establish, because the most common false assurance in radon is a visual one. A running fan and a healthy manometer reading prove that the system is moving air and holding suction under the slab. They do not prove that the indoor radon concentration is below the action level. Those are related but genuinely different questions. A system can hold good suction at the pipe while a new entry route, a renovation, or a shifted pressure field lets radon in somewhere the suction field does not reach. The manometer is a system health indicator, not a measurement of what you are breathing.
That gap is why the standard guidance pairs the annual inspection with a retest every two years, and after any repair, replacement, or significant change to the building [1]. The retest is what closes the loop. Everything else in the audit is there to catch a failure early enough that you are not relying on the next scheduled test to discover it, which in the worst case would mean two years of unmitigated exposure before anyone noticed the fan had stopped.
The reverse limit is worth stating too. A test result is a snapshot of a period, not a permanent property of the house. Radon concentrations swing with barometric pressure, wind, rain, frozen or saturated ground, and the stack effect that develops when a heated house sits in cold air, and the swing between the highest and lowest days in a year can be several fold in the same room. That is why a short term test in a stable winter week and a short term test in an open windowed June week can disagree substantially without either being wrong, and why a long term measurement of ninety days or more is the better estimate of what you are actually exposed to over a year.
FAQ
What’s the minimum I should check each year if I have a mitigation system?
At minimum, check the manometer reading and confirm the fan sounds normal. Combine this with your broader annual home safety routine for consistency.
How often should I retest if I already have a mitigation system?
The common guidance is every two years, and additionally any time the fan is replaced or serviced, the system is altered, or the house undergoes work that changes its foundation, envelope, or ventilation. A retest is also worth doing after any period where the manometer showed the fan had been off, because you have no measurement covering that window.
The manometer columns are level. Does that always mean the fan is dead?
Level columns mean the system is not generating suction, but the fan itself is only one of the possible causes. Check that the fan has power, since a tripped breaker or an unplugged outlet in an attic or on an exterior wall is a common and easily missed explanation. A disconnected or cracked sensing tube at the manometer will also read level while the fan runs normally. If power is present and the tube is intact, a silent or humming fan that moves no air has usually reached the end of its life.
How long does a radon mitigation fan last?
Continuous duty radon fans are typically expected to run for several years of uninterrupted operation, with manufacturer warranties commonly in the five year range, and many units run well beyond that. Because they run twenty four hours a day, every day, they accumulate operating hours quickly compared with intermittently used equipment. The practical implication is that fan failure is a matter of when rather than if, which is precisely why the manometer check belongs in an annual routine.
An annual visual/audio check supplements but doesn’t replace your scheduled 2-year retest — both matter.
References
- How do I know if my radon mitigation system is working properly?. U.S. Environmental Protection Agency
These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Content is for informational purposes only and is not medical advice; consult a qualified healthcare provider before starting any supplement. As an Amazon Associate we earn from qualifying purchases.
