A radon mitigation system is one of the most set-and-forget home improvements available — but “set and forget” for 10 years without a single check is how homeowners discover their fan stopped working three years ago and they never noticed because no one looked at the manometer. This guide provides a structured 5-year maintenance schedule with specific tasks at monthly, annual, biennial, and 5-year intervals, plus a documentation approach that keeps your system’s history organized for future reference and eventual resale.
Monthly Tasks (5 Minutes or Less)
Check the U-Tube Manometer
Look at the liquid-filled gauge mounted on the riser pipe. The colored liquid column should be displaced — one side higher than the other. This indicates the fan is generating negative pressure in the pipe and the system is operating.
- Displaced liquid: Normal operation. No action needed. Make a mental note that you checked.
- Level liquid (equal on both sides): System is not generating suction. Check whether the fan outlet is live (plug a lamp into the same outlet), check the circuit breaker, and listen for fan operation. If power is confirmed and the manometer still shows no pressure: the fan has likely failed. Contact a certified mitigator.
- Liquid significantly lower than at installation: Fluid may have evaporated over years. Contact your installer for guidance on replenishing the manometer fluid.
Listen for the Fan
From a location below the attic-mounted fan — typically the room directly below — listen for the characteristic low hum of fan operation. New sounds (grinding, squealing, rattling) that were not present previously warrant investigation. Complete silence from a location where you previously could hear light fan operation suggests the fan may have stopped.
Annual Tasks (30–60 Minutes)
Physical Fan Inspection
Access the fan location (attic, exterior, or garage) and physically inspect:
- Fan housing: check for visible cracks in the plastic housing. Any crack warrants replacement regardless of whether the fan is still running — a cracked housing discharges radon at the fan location.
- Pipe connections at the fan inlet and outlet: confirm both connections are secure. Press gently on each connection — there should be zero movement.
- Fan wiring: confirm the power cord or hardwired connection is undamaged and not stressed or kinked.
- Mounting: confirm the fan is securely mounted and not vibrating against adjacent framing.
Discharge Cap Inspection
Inspect the discharge cap at the pipe termination (above the roof or gable end):
- Confirm the cap is intact — not cracked, missing, or corroded
- Confirm the cap opening is unobstructed — no bird nesting, leaf accumulation, or ice blocking
- Confirm the pipe below the cap is securely fastened and has not shifted
- For roof penetrations: inspect the pipe boot flashing for signs of water intrusion around the pipe
Visible Pipe and Label Inspection
- Inspect the visible riser pipe for cracks, impact damage, or separation at joints
- Confirm pipe straps are secure along the full visible run
- Confirm the required AARST warning label is still present and legible
- Note any new cracks in the slab near the suction point penetration — document with a photograph if new cracking is observed
Slab Sealing Condition
- Inspect the core hole seal at the slab — the hydraulic cement around the riser pipe should be intact with no gaps
- Inspect control joints and expansion joints for sealant degradation — polyurethane caulk has a useful life of 10–15 years; sealant that is cracked or pulling away should be reapplied
- Note any new visible slab cracks — photograph and date for your records
Every Two Years: Radon Retest
EPA recommends retesting a mitigated home every 2 years. The biennial radon test is the most important scheduled maintenance task because it is the only confirmation that the system is achieving adequate radon reduction, not just that it is running.
- Purchase a 48-hour charcoal canister test from a certified lab ($15–$30) or an alpha track long-term detector for a 90-day test ($25–$45)
- Place in the lowest livable level of the home, breathing zone height (20+ inches above floor), away from windows, HVAC vents, and the suction point
- Follow closed-house protocol for charcoal canisters
- Record the result and date in your radon system documentation file
- If the result is at or above 4.0 pCi/L: investigate immediately — see the diagnostic guide in the Troubleshooting section of this knowledge base
- If the result is between 2.0 and 4.0 pCi/L and was previously below 1.0 pCi/L: this trend warrants investigation even though it is below the action level — fan performance may be declining
Every 5 Years: Comprehensive System Review
Fan Performance Assessment
At the 5-year mark, consider having a certified mitigator conduct a professional diagnostic to measure actual fan performance — static pressure at the suction point, airflow rate, and suction field coverage. This provides a performance benchmark and allows comparison with original installation measurements if available. A fan that originally generated 0.10 inches of water column at the suction point and now generates 0.05 may be declining — useful to know before it fails.
At the 5-year mark, the RadonAway manufacturer warranty expires. If the fan has been experiencing any noise issues (grinding, squealing, increased vibration), 5 years is a good time to replace it proactively rather than waiting for failure — especially if it is an exterior-mounted fan with higher weather exposure.
Full Slab and Seal Inspection
After 5 years of foundation settling and seasonal thermal cycles, caulk and sealant that appeared intact at year one may have begun to fail. The 5-year mark is a good time for a thorough inspection of:
- All control joints and expansion joints — reapply polyurethane sealant where the existing sealant is cracked, pulled away, or missing
- The floor-wall joint perimeter — recaulk any sections showing gaps
- Plumbing penetrations — inspect hydraulic cement seals around any pipes through the slab
- Any cracks that have developed since original installation — seal with appropriate caulk or epoxy injection depending on width and activity
Documentation Update
At the 5-year mark, update your radon system documentation file with:
- All biennial retest results to date
- Any service performed — sealing work, fan replacement, suction point additions
- Current system performance assessment results if a professional diagnostic was conducted
- Updated photographs of the fan, manometer, visible pipe, and suction point area
Quick Reference: Maintenance Summary Table
| Frequency | Task | Time Required |
|---|---|---|
| Monthly | Check U-tube manometer (displaced = good) | 5 seconds |
| Monthly | Listen for unusual fan sounds | 30 seconds |
| Annual | Physical fan inspection (housing, connections, mounting) | 10–15 min |
| Annual | Discharge cap inspection | 5 min |
| Annual | Visible pipe, straps, and label check | 5 min |
| Annual | Slab sealing condition review | 10–15 min |
| Every 2 years | 48-hour radon retest (charcoal canister) | 2 days + $15–$30 |
| Every 5 years | Professional performance diagnostic (optional but recommended) | 1–2 hrs + $150–$300 |
| Every 5 years | Full slab and seal reapplication review | 1–2 hrs |
| Year 7–10 (exterior fan) or Year 10–15 (attic fan) | Fan replacement (proactive or on failure) | 1–2 hrs + $180–$450 |
Frequently Asked Questions
How often should I check my radon mitigation system?
Check the U-tube manometer monthly — 5 seconds, no tools required. Conduct an annual physical inspection of the fan, discharge cap, visible pipe, and slab sealing condition (30–60 minutes). Retest for radon every 2 years. At 5 years, consider a professional diagnostic of fan performance and a comprehensive slab seal inspection.
What maintenance does a radon fan require?
Radon fans require no internal servicing — they use permanently sealed, non-serviceable bearings. Maintenance consists of: monthly confirmation the fan is operating (via manometer), annual inspection for housing cracks and pipe connection security, and replacement when bearings begin to fail (indicated by grinding or squealing sounds) or when fan lifespan is reached (7–15 years depending on installation type).
How do I document my radon system for resale?
Maintain a home radon file containing: original pre-mitigation test result, installer documentation (name, certification number, installation date, system specs, fan model), original post-mitigation test result, all subsequent biennial retest results with dates, any service records, and fan warranty documentation. This file is what satisfies radon disclosure requirements and demonstrates to buyers that the system has been properly maintained and verified over time.
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