Annual system inspection
An installed radon system needs very little, but the little it needs is invisible if nobody looks. This is a ten-minute walk-through once a year.
Everything here is safe for a homeowner. Fan, roof, and electrical work is not on this list, deliberately.
The gauge and the fan
Check the manometer columns are offset, and compare to your commissioning note — hard to reverse later
Level columns mean no suction. Drift from the baseline means something has changed.
Listen at the fan for a steady low hum — hard to reverse later
Silence from a fan that used to be audible is the simplest diagnosis available.
Note any change in noise character since last year
Grinding or a rising whine is bearing wear and precedes failure.
Confirm the dedicated breaker is on
A tripped circuit stops the system silently and costs nothing to check.
Outside
Look at the discharge point for debris, nesting, or damage
A blocked discharge changes performance without any indoor symptom.
Check exterior pipe supports and any exposed run
Weather and impact damage happen, and a separated joint loses the whole system.
In winter, check for ice at the discharge
Seasonal blockage is a real failure mode in cold climates.
Inside
Walk the visible pipe run for damage or modification — hard to reverse later
Renovation is the most common cause of an altered system.
Confirm the sump lid is still sealed if you have one — hard to reverse later
Sump or drainage service frequently leaves the lid unsealed afterwards.
Check visible sealing at the floor-wall joint and penetrations
Sealant shrinks and cracks as a slab moves, and an open joint is a path the fan has to fight.
If you have a crawl space, inspect the membrane for tears
Storage and trades access are the usual causes.
Records and cadence
Confirm you can still find the four documents from installation — hard to reverse later
Credential number, scope, verification report, warranty. Lost paperwork turns a documented repair into an open question at resale.
Note anything done to the house this year that belongs on the retest list — hard to reverse later
Basement finishing, HVAC replacement, drain tile, air sealing, foundation work.
Retest if it has been two years, or if anything on that list happened — hard to reverse later
The gauge does not report the concentration in the room. Only a test does.
What this checklist does not cover
A checklist that pretends to be complete is worse than one that states its edges. These are the things deliberately left out, each with somewhere better to go:
- This is a homeowner walk-through. It is not a professional system inspection and does not substitute for one.
- It never asks you to open a fan, touch wiring, or go on a roof. Those are hazards and, in states that credential radon work, credentialed activities.
- It cannot detect a suction field that has stopped covering part of the slab. That needs instruments.
Confidence and limits of this page
Every decision resource on this platform states its own boundaries. This is not a disclaimer — it is the part of this checklist you should read before relying on it.
- What we knowClaims on this page we stand behind, each traceable to an approved source or to observable structure.
- A manometer reports whether the fan is developing suction, and level columns are an unambiguous fault indication.
- Renovation is a common cause of altered pipe runs and unsealed sump lids, which is why the visual walk is worth doing.
- Retesting every two years while a system is in service reflects standard published guidance.
- What we do not knowQuestions you may reasonably have that this page does not answer.
- Whether the suction field still covers the whole slab. A homeowner cannot check that, and a passing walk-through does not establish it.
- How long any component has left.
- What research would settle itWhat it would actually take to answer the above — naming it is the difference between honesty and hedging.
- Longitudinal inspection data on mitigated houses would establish which of these checks actually catch problems and at what rate. This list reflects failure modes we can describe rather than frequencies we have measured.
- A comparison of annual-walkthrough households against non-inspecting households would quantify whether the habit changes outcomes.
- What we do not claimClaims you might expect to find here and will not, with the reason.
- We do not claim this replaces a professional inspection.
- We do not claim a passing walk-through means your house is below the action level.
- We do not publish component lifespans in years.
- What we cannot independently verifyFacts this page relies on that we could not confirm ourselves.
- What your manometer read at commissioning, unless you recorded it. Without that baseline, drift is invisible.
The annual maintenance check, item by item
What it shows. What to look at once a year, what normal looks like for each item, and which single observation matters most.
Authored as SVG in this repository, with real text nodes and a long description for screen readers. Reusable under CC BY 4.0 — see the diagram library.
Sources
- U.S. EPA — Radon
- U.S. EPA — Consumer’s Guide to Radon Reduction
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