Why Is Water Dripping From My Bathroom Extractor Fan?
For water droplets appearing from a bathroom ceiling or wall extractor fan, especially after showers, during cold weather or after heavy rain.
What this usually means
Water dripping from a bathroom extractor fan is commonly condensation forming inside the duct rather than a plumbing leak. Warm, moisture-laden bathroom air can condense when it reaches cold ducting in a loft or roof space, then run back towards the fan if the duct is poorly insulated or falls the wrong way. Vertical ducts may also need a condensation trap. Rain entering an external grille or roof terminal is another possibility, so the timing of the drip matters.
What may be causing this
Condensation is forming inside cold ducting
Clues: Dripping is worst after a hot shower and in cold weather, especially where the duct runs through an unheated loft or ceiling void.
What to do: The duct route should be checked for insulation, excessive length and cold sections. Manrose advises insulating ducts that pass through cold voids.
The duct falls back towards the fan
Clues: Water returns to the fan after the fan stops, or the duct has a sag or visible low point where condensate can collect.
What to do: Horizontal ducting should be arranged to fall towards the outside termination rather than back towards the fan, following the fan manufacturer's installation instructions.
A vertical duct has no effective condensation trap
Clues: The fan vents upwards through a ceiling or roof and water appears after moisture-heavy use in cold conditions.
What to do: Manufacturer guidance commonly calls for a condensation trap in vertical moisture-laden extract ducts. This should be installed and drained correctly by a competent person.
Rain is entering through the external terminal
Clues: The drip is linked to heavy or wind-driven rain rather than shower use, or the external grille, cowl or roof terminal is damaged or badly positioned.
What to do: Have the external termination and weathering checked. A wall grille, roof terminal or flashing defect may need repair before changing the fan.
The fan is not extracting effectively
Clues: The bathroom remains steamy for a long time, mirrors stay wet, mould is developing and airflow at the fan is weak.
What to do: Check only user-cleanable grilles as the manufacturer permits. A blocked, undersized, poorly ducted or failing fan may need professional cleaning, repair or replacement.
How to check what is happening
Condensation inside the duct is more likely than rain ingress.
The external vent, roof terminal, flashing or wall penetration needs checking for rain entry.
The duct arrangement can allow condensate to collect and return to the fan.
Poor extraction may be increasing the amount of condensation forming in the system.
Can you fix this yourself?
You can safely observe when the drip happens and inspect only accessible ducting or the outside terminal without opening electrical equipment. Correcting duct falls, adding insulation or a condensation trap, and dealing with a wet mains-powered fan should be handled by a competent installer.
- Torch
- Phone camera
- Fan installation manual
What you can safely try
- 1
Work out whether the trigger is shower steam or rain
Note whether water appears after bathing, during cold weather, during heavy rain, or all three. This simple timing check separates internal condensation from external weather ingress surprisingly well.
- 2
Inspect only safely visible ducting
If you can view the duct in a loft without disturbing electrical equipment, look for uninsulated sections, sags, low points or a route that slopes back towards the fan. Do not dismantle the fan or wiring.
- 3
Look at the external termination from a safe position
Check whether the wall grille, cowl or roof terminal looks broken, missing or obviously exposed to rain entry. Avoid ladders or roof access unless you are competent and equipped for it.
- 4
Treat water inside the fan as an electrical issue
If the fan body itself is wet or water is reaching electrical parts, stop using it and isolate the circuit if you can do so safely. Do not rely on the fan continuing to run normally.
- 5
Have the duct system corrected, not just the drip wiped away
A competent installer can insulate cold ducting, correct the fall, fit a condensation trap where required, improve the external termination and confirm that the fan is correctly sized and wired.
Call an electrician if…
- Water is dripping through or around the electrical fan body.
- The fan trips an RCD or circuit breaker, smells hot, buzzes abnormally or stops working.
- Inspection or repair requires opening fixed electrical equipment or entering a roof.
- The external roof or wall termination appears damaged or rainwater is entering the building fabric.
- Persistent condensation or mould remains even after the ventilation route is corrected.
Get the right professional.
This problem can have more than one cause. Start with the checks above: an electrician is the usual first route, while a roofer may be more appropriate when the clues point that way.
Sources used for this guide
We prefer primary UK guidance, regulators and manufacturers for technical and safety-sensitive claims.
- Installation Instructions — Centrifugal Inline FansManrose
- How to Choose a Ventilation FanManrose
- Spring cleaning electrical safety advice — extractor fansElectrical Safety First
Last reviewed: 31 August 2026. Home Manual updates review dates only when the substance of a guide is checked or changed.