There is a particular kind of panic that hits at 2 AM when you walk into your bedroom and hear dripping.
Not rain. Not a tap you forgot to close.
Your aircon.
And it is quietly destroying your parquet flooring while you stand there in the dark, wondering if you should be calling someone or just shoving a towel under it and going back to bed.
Here is the truth: that drip is not a minor inconvenience. In Singapore’s climate, a leaking aircon is your unit sending up a distress flare. Ignore it for a few days and you are looking at warped flooring, toxic mold in your walls, and potentially a $1,000 fine from the NEA.
But if you act fast? It is usually a straightforward fix.
This guide will walk you through exactly what to do — right now, tonight, and over the next few days.
First Things First: Stop the Damage Before You Do Anything Else
Before you start googling causes or watching YouTube repair videos, protect your home.
Water and electricity are a dangerous combination, and your aircon has plenty of both.
Step 1 — Cut the power properly. Do not just hit the remote. Walk to the isolator switch next to the indoor unit or flip the correct circuit breaker. If water reaches the main PCB (the aircon’s circuit board), what started as a simple $80 drainage flush can turn into a $300+ motherboard replacement overnight.
Step 2 — Move everything out of the way. Laptops, extension cables, rugs, wooden furniture — get them away from the drop zone immediately. Your parquet floor is especially vulnerable. Water seeps under the planks fast, and once they start warping, there is no fixing it without full replacement.
Step 3 — Catch the drip. Place a bucket directly under the unit. Press a thick, dry towel flat against the skirting board to stop water from tracking sideways. You are buying yourself time.
Step 4 — Wipe the exterior only. A dry microfiber cloth on the plastic casing is fine. Do not open the front panel and start poking around the internals while they are wet. Leave the actual diagnosis to a technician.
Water already dripping down your wall? WhatsApp Decom Aircon now for same-day emergency response. We clear blockages fast.
Why Singapore Makes Aircon Leaks So Much Worse
This is not a coincidence. Singapore’s climate is brutal on air conditioning systems in a way that most homeowners do not fully appreciate.
Your aircon does two things simultaneously: cools the air and pulls enormous amounts of moisture out of it. On a typical Singapore day, a single bedroom unit can extract several litres of water from the air. All of that condensation has to drain somewhere — through a PVC pipe that runs through your walls and out of the building.
When that drainage system works perfectly, you never notice it. When it fails, everything that water was supposed to carry away ends up in your room instead.
The high humidity also creates the perfect environment for the thing that blocks most Singapore drainage pipes: a thick, slimy substance that technicians call aircon jelly. More on that in a moment.
5 Real Reasons Your Aircon Is Leaking Water
To fix this permanently, you need to understand what is actually going wrong inside the unit. Here are the five most common causes — and how to tell which one you are dealing with.
1. Clogged Drainage Pipe (The Jelly Problem)
This is responsible for over 70% of aircon leaks in Singapore. Nothing else comes close.
Here is the science. Inside your aircon unit, it is dark, constantly damp, and cool. That environment is paradise for bacteria and algae. Every time your unit runs, it pulls in warm air from the room — and with it, microscopic particles: dust, skin cells, fabric fibres, and more.
Over months, those particles mix with the condensation water and start to ferment. The result is a thick, translucent, brownish sludge that slowly builds up inside your PVC drainage pipe. Technicians see it every day. It looks like clear gel. It smells musty. And once it fully blocks the pipe, the water has absolutely nowhere to go.
So it backs up. Fills the internal drain pan. And then overflows directly into your room.
How to tell: The leak is usually steady and constant while the unit is running. You may also notice a faint musty smell coming from the unit.
2. Dirty Fan Coil and Filters
Your aircon needs airflow to function. It works by pulling warm room air over cold evaporator coils to cool it down — and that process only works if air can actually move through the system freely.
When the filters and the delicate aluminium fins on the fan coil are choked with dust, airflow drops dramatically. The cold air gets trapped. The coils get colder and colder until — without enough warm air to regulate the temperature — the condensation on them freezes solid.
Eventually, either you switch the unit off or the ice gets too heavy. Either way, it melts fast. And the drain pan underneath was built to handle a slow, steady trickle of condensation, not a sudden flood of melting ice. It overflows.
How to tell: The unit runs fine for a while, then suddenly starts dripping heavily. You might also notice the aircon is not cooling as well as it used to.
3. Poor Installation or Bad Gradient
This one is more common in newer flats than most people realise.
The drainage pipe inside your wall needs to be installed at a specific downward angle — called the gradient — so gravity pulls the water out naturally. If the pipe was laid too flat, or (worse) tilted very slightly upward, the water pools instead of draining. Over time, it backs up and leaks.
We see this constantly in HDB BTO flats where the original contractors rushed the installation. It is not always obvious from the outside, but the problem is built into the geometry of the unit from day one.
How to tell: If your unit has been leaking on and off since the day you moved in, or you hear a soft gurgling sound while the unit runs, poor gradient is very likely the cause.
4. Cracked or Warped Drain Pan
Every indoor unit has a drain pan sitting underneath the evaporator coils. Its one job is to catch condensation and channel it into the pipe.
After five or more years of constant temperature fluctuations and thousands of litres of water, plastic pans warp and crack. Older metal pans rust straight through. Once the pan is compromised, water drips right through the base of the unit before it ever reaches the drainage pipe.
How to tell: The leak appears even when the unit has just been serviced and the drainage pipe is clear. The drip often comes from the very bottom edge of the unit casing.
5. Low Refrigerant (Gas Leak)
This one catches homeowners off guard because gas and water seem unrelated. They are not.
If your refrigerant level has dropped — usually due to a slow leak in the copper piping — the pressure inside the system drops with it. This triggers the exact same ice-and-melt cycle as a dirty coil. The evaporator freezes over, the ice melts too fast, the pan overflows, and water ends up on your floor.
How to tell: The unit is leaking water AND blowing air that is barely cool. Both symptoms together almost always point to a refrigerant issue.
HDB, Condo, or Landed? Your Environment Changes Everything
Where you live in Singapore directly affects how quickly your aircon drainage system clogs — and how often it needs attention.
If you are on a high floor HDB unit and run the aircon mainly at night, a standard servicing schedule every three to four months is usually sufficient.
But if you live in a ground-floor condo, a terrace house, or a semi-detached near heavy foliage, an expressway, or an active construction site — your unit is pulling in significantly more airborne particles every single day. Pollen, exhaust particulates, construction dust. All of it ends up in your drainage pipe.
For landed property owners: clear your drainage lines every two to three months, not four to six. What works for a 15th-floor HDB unit is not enough for a ground-floor landed house. The environment outside your window is simply too different.
What a Professional Fix Actually Looks Like
You can wipe up the water. You can rinse the user-accessible filters in your sink. These are fine habits.
But here is the problem with attempting more than that yourself: blowing air into a blocked drainage pipe — one of the most common DIY attempts — almost always pushes the jelly blockage deeper into your walls. What was a 20-minute vacuum job from a technician becomes an excavation of your plastered wall. It happens more often than you would think.
Here is how Decom Aircon actually resolves the problem:
High-Powered Vacuum Clearance Instead of pushing the blockage, we pull it out. Industrial-grade wet/dry vacuums applied directly at the drainage exit point suck the jelly, algae, and sludge clean out of the system. Most standard leaks are resolved in 20 to 30 minutes. The pipe is left completely clear.
Deep Chemical Flush For units where the fan coil is heavily choked with years of built-up grime, a vacuum alone will not be enough. A chemical flush uses specialized alkaline solutions to dissolve hardened dirt on the aluminum fins, kill the bacteria in the drain pan, and restore proper airflow. Not every unit needs this — but when it does, nothing else comes close.
Not sure whether you need a standard wash, a chemical flush, or a full dismantle? Read our breakdown on Chemical Wash vs. Chemical Overhaul to understand exactly what each process does and when each one is necessary.
Correcting the Gradient If the inspection reveals a BTO installation gradient problem, we fix the geometry. That might mean adjusting the positioning of the fan coil unit or rerouting the PVC pipe to ensure water flows downward consistently. Clearing today’s blockage means nothing if the drainage path itself is the root cause.
No surprise bills. If you want to know exactly what you should be paying — for a drainage flush, a gas top-up, or a chemical overhaul — without getting caught off guard by hidden fees, check our Aircon Servicing Price Guide Singapore → for a fully transparent breakdown of current market rates.
Ready to stop the drip permanently? WhatsApp Decom Aircon now — same-day slots available for emergency drainage clearance.
The Real Cost of Waiting
An aircon leak that gets fixed today costs between $60 and $150. That same leak, ignored for two weeks, can cost you:
- Wall replastering and repainting: $300–$800
- Parquet floor replacement (per room): $1,500–$4,000
- Toxic mold remediation: $500–$2,000
- NEA fine for water dripping onto neighbours: up to $1,000
- Aircon PCB replacement from water damage: $300–$500
The puddle on your floor is not the problem. It is the symptom of a system that is already struggling. And in Singapore’s climate, it does not get better on its own.
Frequently Asked Questions
How much does it cost to fix a leaking aircon in Singapore?
A standard drainage blockage cleared with a professional vacuum typically costs $60 to $100 per unit. If the fan coil needs a chemical wash as well, or the refrigerant requires topping up, the total can range from $150 to $250. See our full price guide for a detailed breakdown by service type.
Can I fix a leaking aircon myself?
You can clean the user-accessible filters — that is always a good habit. But clearing a blocked drainage pipe without professional vacuum equipment almost always makes things worse. Blowing air into the pipe pushes the jelly blockage deeper, turning a simple job into a wall excavation. For anything beyond filter cleaning, call a technician.
Is a leaking aircon actually dangerous?
Yes, in two specific ways. Water dripping onto the PCB or wiring inside the unit can cause a short circuit or fire. Separately, persistent leaks create the damp, dark conditions that toxic black mold needs to grow inside your walls and fan coil — which degrades your indoor air quality and can trigger serious respiratory issues over time.
Why does my aircon only leak when it is turned off?
This is almost always melting ice. If your unit has clogged filters or low gas, ice forms on the evaporator coils while the unit is running. When you switch it off, that ice melts quickly — far too fast for the drain pan to handle. The result is a temporary but heavy flood right after shutdown.
How often should I service my aircon to prevent leaks?
For most Singapore homes: every three months for standard servicing. For ground-floor or landed properties near foliage, construction, or busy roads: every two months. For units that run more than eight hours a day: consider monthly checks on the drainage line.
Decom Aircon provides emergency aircon repair, drainage clearing, chemical wash, and full relocation services across Singapore. WhatsApp us now for a fast response.
Leave A Comment