What Causes an Aircon Water Leak?
Woke up to a wet patch on the bed, or a steady drip on the floor? It’s stressful, but it’s usually a quick fix.
We’re Aircon Servicing Ang Mo Kio, the local service of Cool Earth Aircon, which Brian started in 2007 as a one-man workshop. Aircon water leak repair is one of the jobs our team gets called out for most in the estate.
Here’s the thing: every aircon makes water. As warm, humid air passes over the cold coil, moisture condenses and drips into the drain pan, then runs out through the condensate drain line. A leak means that water has found another way out.
In most homes, the cause is one of these:
- A choked drain line, where dust and slime block the pipe so water backs up
- A drain pan that is cracked, tilted or full of sludge
- Worn pipe insulation on the copper piping, so cold pipes sweat onto the wall
- An indoor unit that is not level, so water tips forward instead of draining
Singapore’s weather makes the first one worse. Gree’s Singapore aircon guide explains that year-round humidity lets dust and moisture combine into a slimy biofilm, which narrows the drain pipe until water backs up and spills from the front of the unit.
Age matters too. According to a Remember Singapore history of the town, the first flats in Ang Mo Kio were completed in 1973. In the older HDB blocks, ageing piping makes leak repairs a common job.
Our technician finds which cause applies before quoting. That way, the fix stops the leak instead of hiding it for a week.
How Is the Leak Fixed?
Our technician starts at the fan coil unit and follows the water. The steps run in this order:
- Check the drain pan for cracks, sludge and level.
- Test the drain line by running water through it.
- If the line is choked, pull out the blockage with a vacuum flush.
- Inspect the pipe insulation and the trunking along the wall, especially on older runs where the insulation has gone brittle.
- Run water through the system again to prove it drains freely.
You pay after the job. If the same leak returns within 90 days, we come back and fix it at no extra charge.
Prices depend on the cause. A February 2026 cost guide from Homejourney puts typical leak repairs in Singapore at $50 to $300 per unit, which is why we diagnose first and quote after.
When Is an Overhaul the Better Fix?
Some leaks keep coming back because the drain pan is full of jelly sludge. This is a thick layer of slime and mould that re-chokes the line soon after each flush.
Clearing the pipe helps for a while, but the source is still sitting in the pan. In that case, the lasting fix is a chemical overhaul, where we take the unit apart and soak and scrub the pan. It’s quoted separately, and you decide before any work starts.
Is dirt building up but no sludge has set in yet? A chemical wash flushes the drain parts with the unit still on the wall.
Common Problems We Solve
Water dripping onto beds and floors
This is the most common call. Usually it’s a choked drain line, and we clear it on the spot.
While you wait for us:
- Switch the unit off.
- Put a towel below the drip.
- Move bedding and electronics out of the way.
Water stains on the wall
Stains below the unit or along the pipe run often point to worn pipe insulation or a drain connection that has come loose. Left alone, they damage paint and plaster.
The usual suspects:
- Brittle insulation where the cold copper pipe sweats
- A drain connection that has worked loose over the years
Leak only at night
Units run longer and colder overnight, so they produce more water. A drain line that is half blocked copes in the day and overflows at night.
A frozen coil can also play a part. Gree’s guide notes that when the ice melts, more water lands in the pan than the drain can clear.
Leak right after servicing
Loosened dirt can settle in the line, or a panel may not be seated properly. If the leak follows our own servicing, the 90-day warranty covers it.
What Can You Do Before the Technician Arrives?
A few quick steps keep the damage small:
- Switch the unit off at the remote and at the wall switch, especially if water is near a power point.
- Put a towel or a bucket below the drip, and move bedding or electronics out of the way.
- Leave the drain pipe and the unit alone. Pulling the pipe or opening the unit yourself can crack the drain pan or loosen a connection.
- Take a photo or a short video showing where the water comes out.
- Send it on WhatsApp with your Ang Mo Kio address.
That last step helps a lot. Our technician can bring the right tools and, where the cause is clear, quote a likely price before the visit.
One more tip: empty the bucket once the leak is fixed. The National Environment Agency lists pails and similar containers as places where Aedes mosquitoes can breed, so don’t leave standing water around.
Older HDB Flats in Ang Mo Kio
Many blocks in Teck Ghee, Cheng San, Chong Boon and Kebun Bahru were built in the late 1970s and 1980s, and their drain piping and insulation have aged with them. Repeat leaks are more common in these flats. For that reason, we check the whole drain path, not just the pipe end.
To keep drains clear between visits, book general aircon servicing every 3 to 4 months. Each visit includes a drain line flush. If you run 2 to 4 units, it’s easiest to service them all in one go.
For anything else that has gone wrong with your unit, see aircon repair. Got a drip right now? Send us a photo on WhatsApp, and we’ll sort out your aircon water leak repair fast.
