Why Your Aircon Produces and Leaks Water
An aircon leaking water is one of the most common and urgent problems Yishun homeowners face. Billy Aircon Yishun, led by Thomas Lim with a dedicated 3-person team, handles leak repair calls across Yishun, Khatib, Nee Soon, and Springleaf regularly. Unlike a gradual reduction in cooling performance, water dripping from your aircon demands immediate attention. Left unchecked, a leaking aircon can damage your walls, flooring, furniture, and electronics.
With professional aircon servicing, most leaks can be prevented through regular maintenance. Understanding what is happening inside your aircon when it leaks helps you respond appropriately.
When warm, humid air from your room passes over the cold evaporator coil, moisture condenses on the coil surface. In Singapore’s extremely humid climate, your aircon can produce litres of condensate water every day. This water normally collects in the drain pan and flows out through a drain pipe. When any part of this drainage pathway is blocked, water overflows and leaks into your room.
Clogged Drain Pipe - The #1 Cause of AC Water Leaks
This is the number one cause of aircon water leaks, responsible for over 60% of all leak cases we attend across Yishun’s HDB estates. The condensate drain pipe carries water from the drain pan to the building’s drainage point. Over time, this pipe accumulates slime, algae, dust, and debris. In Singapore’s warm and humid conditions, biological growth inside the drain pipe is inevitable.
How to recognise this cause:
- Water drips steadily from the front or side of the indoor unit
- The dripping gets worse when the aircon has been running for several hours
- Cooling performance may still be normal
- The problem starts gradually and worsens over weeks
Our fix: We flush the drain pipe using pressurised water or a specialised vacuum device to clear the blockage completely. We also clean the drain pan. In severe cases, we may need to reposition or replace a section of the drain pipe.
Prevention: Regular aircon servicing every 3 to 4 months includes drain pipe flushing, which prevents blockages from causing leaks.
Dirty Filters and Coil Causing Overflow
Heavily clogged filters restrict airflow over the evaporator coil, causing the coil temperature to drop below normal. When the coil gets too cold, condensation increases dramatically. Worse, the excess cold can cause moisture to freeze on the coil. When the aircon cycles off, this ice melts and floods the drain pan.
How to recognise this cause:
- Large amounts of water appear suddenly, not a steady drip
- You see ice or frost on the evaporator coil
- The leak happens after the aircon has been off for a while
- Aircon may also be not blowing as cold as it should
Our fix: We clean the filters thoroughly and, if needed, perform a chemical wash to strip away the grime layer disrupting airflow.
Low Refrigerant Gas and Ice Buildup
When refrigerant levels drop below optimal, the pressure inside the evaporator coil drops too low, causing the coil temperature to plunge below freezing point. Ice builds up over hours of operation and then melts when the system cycles off, overwhelming the drain pan.
How to recognise this cause:
- Ice visible on the evaporator coil or copper pipes
- A noticeable drop in cooling performance alongside the water leak
- The aircon runs continuously
- Large volume of water when ice melts
Our fix: We test refrigerant pressure, detect and repair any leaks, and perform a gas top up to restore the correct charge. Once refrigerant levels are restored, icing stops.
Faulty Installation and Drain Pipe Gradient Problems
Poor installation is a common but often overlooked cause of aircon water leaks. This is particularly relevant in Yishun where many new BTO flats and EC units have been recently fitted with aircon systems.
Incorrect drain pipe gradient - The drain pipe must slope downward continuously. If any section runs uphill, water pools and eventually backs up.
Loose or disconnected drain pipe - If the drain pipe connection to the drain pan is loose, water drips from the junction point.
Improper unit levelling - The indoor unit must be mounted perfectly level with a slight tilt toward the drain pan side.
Inadequate insulation on piping - Cold refrigerant pipes produce condensation on their exterior if not properly insulated.
Our fix: We inspect the installation for gradient issues, loose connections, and improper levelling. We handle all major brands including Daikin, Mitsubishi, and Panasonic.
Cracked or Overflowing Drain Pan
Over many years, the drain pan can crack due to thermal stress. A cracked pan allows water to bypass the drain pipe. This is more common in older units found in mature Yishun HDB blocks.
Our fix: We inspect the drain pan for cracks, corrosion, and sediment buildup. Minor cracks can sometimes be sealed, but severely damaged pans require replacement.
Frozen Evaporator Coil - What Triggers Ice Formation
Any condition that causes the evaporator coil to drop below 0°C can lead to ice formation:
- Low refrigerant gas
- Severely clogged filters
- Dirty evaporator coil
- Faulty fan motor
- Thermostat set too low in a small room
Our fix: We identify the root cause of the ice formation and address it.
How Urgent Is an Aircon Water Leak?
An aircon water leak should be treated as urgent:
Water damage to your home - Water running down walls causes paint peeling, plaster damage, and flooring damage. In Yishun HDB flats and condos, water can affect the unit directly below.
Mould and mildew growth - Water seeping behind walls creates mould colonies that spread rapidly in Singapore’s warm, humid environment.
Electrical hazards - Water and electricity are a dangerous combination.
Damage to the aircon itself - A $50 drain flushing today can prevent a $400 to $1,200 compressor replacement later.
Liability to neighbours - In HDB flats, water leaking from your aircon can damage the unit below yours.
What to Do When Your Aircon Drips Water
- Turn off the aircon to stop condensation production
- Place towels or a container to catch dripping water
- Move electronics and valuables away from the leak area
- Check the obvious - open the front panel and check if the filters are clogged
- Do not attempt to dismantle the unit
- Call Billy Aircon Yishun for same-day repair
How We Diagnose and Repair the Leak
Step 1 - Visual inspection of the indoor unit for water, ice, and dirt.
Step 2 - Filter and coil check to assess evaporator coil condition.
Step 3 - Drain system test by pouring water into the drain pan and observing drainage speed.
Step 4 - Drain pipe flushing using pressurised water or vacuum equipment.
Step 5 - Refrigerant check if ice formation is present.
Step 6 - Installation inspection to verify unit levelling and drain pipe gradient.
Step 7 - Testing for at least 20 minutes to verify no water accumulates.
Book Same-Day Leak Repair Now
Most leaks are caused by simple drain blockages that our technicians resolve in 30 to 45 minutes.
WhatsApp us at +65 9459 8727 to book an urgent leak repair. Same-day service available for morning bookings. Serving HDB flats, condos, and commercial properties across Yishun, Khatib, Nee Soon, and Sembawang.
