Why Is Your Aircon Leaking Water?
Water dripping from your aircon is more than an annoyance — it can damage your walls, furniture, flooring, and electrical fittings. In Singapore’s humid climate, an aircon produces a significant amount of condensation water during normal operation. This water is supposed to flow through the drain pipe and exit harmlessly through a floor trap or external drainage point.
When something disrupts this drainage path, water backs up inside the unit and overflows onto your wall or floor. Billy Aircon sees water leak cases every single day. The good news is that most aircon water leaks can be diagnosed and repaired in a single visit.
Understanding the cause of your leak helps you decide whether it is something you can address yourself or whether you need professional help. Below, we cover every common cause and what Billy Aircon does to fix each one.
The 6 Most Common Causes of Aircon Water Leaks
1. Clogged Drain Pipe
This is the number one cause of aircon water leaks in Singapore — responsible for roughly 70% of all leak calls Billy Aircon receives.
Your aircon’s drain pipe carries condensation water from the drainage tray inside the indoor unit to an external discharge point. Over time, dust, mould, algae, and sludge accumulate inside this narrow pipe. Eventually, the blockage restricts water flow, and condensation backs up in the drainage tray until it overflows.
Signs: Water dripping slowly but steadily from the bottom of the indoor unit. The leak may start small and worsen over days as the blockage grows.
How we fix it: Billy Aircon clears the drain pipe using a combination of vacuum suction, pressurised water flushing, and chemical cleaning. We also inspect the drain hose for kinks or damage that could cause future blockages.
Prevention: Regular aircon servicing includes drain pipe flushing as a standard step. Quarterly servicing keeps the pipe clear and prevents blockages from forming.
2. Dirty or Overflowing Drainage Tray
The drainage tray (also called the drip tray) sits beneath the evaporator coil and collects condensation before channeling it to the drain pipe. When this tray accumulates dirt, mould, or debris, water cannot flow to the drain outlet properly. The tray fills up and overflows.
In some cases, the drainage tray can crack or warp due to age or thermal stress, creating a direct leak point.
Signs: Water dripping from the front or sides of the indoor unit, rather than from the bottom centre where the drain connection is.
How we fix it: We remove the drainage tray, clean it thoroughly, check for cracks or warping, and reinstall it with correct alignment. If the tray is damaged beyond repair, we replace it.
3. Dirty Air Filter Causing Ice Buildup
A clogged air filter restricts airflow over the evaporator coil. When airflow is insufficient, the coil temperature drops below freezing point, causing moisture in the air to form ice on the coil surface. When the aircon cycles off or the ice melts, a large volume of water runs off at once — overwhelming the drainage tray and causing a sudden leak.
Signs: Intermittent leaking, often worse after the aircon has been running for several hours. You may also notice your aircon is not cold because the ice-covered coil cannot absorb heat effectively.
How we fix it: We clean the air filter and, if ice has already formed, let the unit defrost completely before restarting. If the problem recurs after filter cleaning, a deeper chemical wash may be needed to clean the coil itself.
4. Low Refrigerant Causing Frozen Coil
Similar to a dirty filter, low refrigerant causes the evaporator coil to freeze. The mechanism is different — instead of restricted airflow, the reduced gas pressure lowers the coil temperature below normal operating range. Ice forms, melts, and overwhelms the drainage system.
Signs: Water leak combined with weak cooling. The copper pipe running from the indoor unit may have ice or frost on it. You may hear a hissing sound near the indoor unit.
How we fix it: A gas top up restores the refrigerant to the correct level. We also perform leak detection to find and repair the source of the gas loss. Without fixing the leak, ice will form again once the new gas escapes.
5. Improper Installation
If your aircon was not installed correctly, water leaks can occur from day one — or develop gradually as components shift. Common installation-related leak causes include:
- Incorrect tilt: The indoor unit must be tilted slightly toward the drain pipe so gravity pulls water in the right direction. If the unit is level or tilted the wrong way, water pools on the opposite side and drips off the edge.
- Drain pipe gradient: The drain pipe must slope downward continuously from the indoor unit to the discharge point. Any upward sections or dips create traps where water accumulates.
- Loose drain hose connection: If the drain hose is not securely attached to the drainage tray outlet, water leaks at the connection point.
- Insufficient insulation on piping: In Singapore’s humidity, uninsulated or poorly insulated pipes cause condensation to form on the pipe surface and drip.
Signs: Leaking starts shortly after installation or after renovation work that may have disturbed the piping. Water may drip from an unexpected location rather than from the unit itself.
How we fix it: Billy Aircon inspects the entire installation — unit tilt, drain pipe gradient, hose connections, and pipe insulation. We correct any defects and test the drainage with water to confirm proper flow.
6. Damaged or Disconnected Drain Pump
Some aircon installations — particularly in condos where the drain point is higher than the indoor unit — use a condensation pump to push water uphill to the drainage point. If this pump fails, water cannot be evacuated and backs up inside the unit.
Signs: Sudden onset of leaking in a unit that previously drained fine. The pump may make a buzzing or clicking sound when it tries to operate.
How we fix it: We test the pump’s operation and replace it if faulty. Condensation pump replacement is a straightforward repair that Billy Aircon completes in a single visit.
DIY Checks Before Calling a Technician
Before reaching for the phone, try these quick checks:
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Check the air filter: Pull it out and inspect it. If clogged with dust, wash it under running water. A dirty filter is the most common root cause behind ice-related leaks.
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Check the front panel: Ensure it is clicked shut properly. A loose front panel can redirect condensation drips outside the drainage tray.
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Look for ice: Open the front panel and inspect the evaporator coil. If you see ice, turn off the aircon completely and let it defrost for 3 to 4 hours. Clean the filter before restarting.
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Check the drain outlet: If accessible, check where your drain hose exits (usually at a floor trap in the bathroom or utility area). Pour a small amount of water into the floor trap to ensure it is not blocked.
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Inspect for tilt: Stand back and look at the indoor unit. It should be very slightly tilted toward the side where the drain pipe exits. If it looks visibly uneven, the mounting brackets may have loosened.
If the leak persists after these checks, professional repair is needed.
Billy Aircon’s Water Leak Repair Process
Step 1: Arrival and Assessment Our technician inspects your indoor unit, identifies the leak location, and determines the cause. We check the drainage system, filter condition, coil condition, refrigerant pressure, and installation quality.
Step 2: Root Cause Explanation We explain what is causing the leak in plain language and provide a repair quote before starting any work.
Step 3: On-the-Spot Repair Most water leak repairs are completed during the first visit. Common repairs include drain pipe clearing, tray cleaning, filter washing, and installation adjustments. More complex issues like gas top up or pump replacement are also handled on site.
Step 4: Flow Testing After the repair, we pour water into the drainage tray to verify it flows correctly through the entire drain path to the external discharge point. This confirms the leak is truly resolved.
Step 5: Warranty All Billy Aircon water leak repairs come with a 90-day warranty. If the same leak recurs within this period, we return and fix it at no additional charge.
Water Leak Repair Pricing
| Repair Type | Typical Cost |
|---|---|
| Drain pipe clearing (vacuum + flush) | $50–$80 |
| Drainage tray cleaning and realignment | $60–$100 |
| Drain pump replacement | $120–$200 |
| Installation correction (tilt, gradient) | $80–$150 |
| Gas top up (if ice-related leak) | $50–$200 |
| Chemical wash (if dirty coil causing ice) | $80–$180 |
Exact pricing depends on the specific issue found during diagnosis. Billy Aircon always quotes before starting work.
Preventing Future Water Leaks
The best way to prevent aircon water leaks is regular maintenance. Billy Aircon recommends:
- Quarterly servicing: Our standard servicing package includes drain pipe flushing, filter cleaning, and drainage tray inspection. This catches potential blockages before they cause leaks.
- Annual chemical wash: A chemical wash removes deep-seated dirt from the evaporator coil and drainage tray, reducing the organic material that causes drain blockages.
- Monthly filter cleaning: Wash your air filters every 2 to 4 weeks. This is the single most effective DIY maintenance task.
Frequently Asked Questions
Is a leaking aircon dangerous?
Water leaks themselves are not immediately dangerous, but they can cause electrical short circuits if water reaches wiring or electrical outlets. Prolonged leaking also damages walls, ceilings, and flooring. Address leaks promptly.
Why does my aircon only leak at night?
Nighttime leaking often occurs because the aircon runs continuously during sleep hours, producing more condensation than usual. A partially clogged drain can handle lower volumes during short daytime use but overflows during extended operation.
Can a water leak damage my aircon permanently?
Indirectly, yes. If the leak is caused by ice buildup from low gas or restricted airflow, the underlying condition puts strain on the compressor. Prolonged compressor strain leads to premature failure.
How quickly can you fix my aircon leak?
Billy Aircon responds to all enquiries within 24 hours and offers same-day appointments for urgent leaks. Most repairs are completed in 30 to 60 minutes during the first visit.
Stop the Leak Today
A dripping aircon gets worse over time, not better. Billy Aircon provides fast, professional water leak repair across Singapore for HDB flats, condos, and landed homes. Every repair comes with a 90-day warranty and transparent pricing.
WhatsApp us at +65 9456 0875 to describe your leak and book a same-day appointment. We will get your aircon dry and working properly again.
