Switch the unit off
Not to fan — off. The unit produces condensate whenever it runs, so leaving it on keeps feeding the leak while you wait.
Home · AC Duct Cleaning · AC Leaking Water: Causes and What to Do First
AC Diagnostics · Dubai & Abu DhabiAC Leaking Water: Causes and What to Do First
An air conditioner removes litres of water from the air every day in a Dubai summer. When that water appears on your ceiling instead of in the drain, the cause is nearly always the drain path — and the damage it does to gypsum is fast.
First ten minutes
Limit the damage
Catch and contain
A tray under the drip and towels around it. Gypsum ceilings absorb rather than shed, so the stain spreads well beyond where the water lands.
Photograph it
Date-stamped, before anything is moved. If this becomes a building or landlord claim, the photograph taken in the first ten minutes is the one that matters.
Tell building management, in a tower
Water tracking through a ceiling void reaches the apartment below faster than most people expect, and the neighbour's claim is easier to handle if you reported it first.
The four causes
In order of how often we find them
Blocked drain line
The most common by a wide margin. Dust, biofilm and algae build up in the condensate line until it backs up and the tray overflows. Clearing it properly means flushing the full run and treating the biofilm, not poking the visible end.
Dirty coil and frozen evaporator
A restricted coil ices, then thaws all at once when the system cycles off. The volume of water released exceeds what the tray can hold. The leak is intermittent, which is what distinguishes it from a blocked drain.
Cracked or misaligned drain pan
Common in older FCUs. The pan corrodes or the unit shifts slightly out of level and the water finds the low corner instead of the outlet.
Poor insulation on the chilled water or refrigerant line
This one is not a leak at all — it is condensation forming on an uninsulated pipe in a humid void. It looks identical from below and is fixed completely differently.
Questions
Answered plainly.
You can sometimes clear the visible end. What that does not do is remove the biofilm growing along the run, which is why the same leak returns within weeks. A proper clear flushes the full length and treats the line.
Any brown staining means the gypsum has absorbed water. Small stains dry and can be sealed and repainted. Sagging or soft board needs cutting out and replacing, and painting over it hides a problem that will come back.
The water itself is condensate, not sewage. The risk is electrical, where it tracks onto a fitting or a socket, and mould, which begins in a sealed damp void within days in this climate.
Intermittent leaking points at a freezing coil rather than a blocked drain — the ice thaws in a burst when the system cycles off. A blocked drain leaks steadily whenever the unit runs.
We identify what needs doing and quote the making good separately under technical services. We will also tell you when a stain will simply dry out and needs nothing.
Priced after an inspection. Fixed in writing.
Every job is scoped against a written checklist you keep, and the price does not move on the day unless you ask for work outside it. Part of AC Duct Cleaning — see also the written checklist.