Finding water dripping from your aircon can be worrying, especially when it runs down the wall or lands near furniture and electrical points.
An aircon usually leaks water because the drainage pipe is blocked, the cooling coil is dirty or frozen, the drain pan is damaged, or the pipe insulation has worn out. Installation faults and failed drain pumps can also cause recurring leakage.
If the dripping is heavy or water is close to electricity, switch off the aircon immediately. Move nearby furniture and electrical items before arranging an inspection.
Aircool Aircon provides aircon water leak inspection and repair for HDB flats, condos, landed homes, offices and commercial properties across Singapore.
What Should You Do When Your Aircon Starts Leaking?
Taking a few simple steps can limit the damage while you wait for professional help:
- Switch off the affected aircon.
- Move furniture and electrical equipment away.
- Put a pail or towel below the dripping area.
- Check whether the removable filter is very dusty.
- Check whether frost or ice has formed on the cooling coil or copper piping.
- Capture a clear photo or short video showing where the water is leaking.
- Contact an aircon technician if it continues.
Do not insert sharp objects into the drainage pipe or pour strong chemicals into the unit.
Why Does an Aircon Produce Water?
While cooling your room, the aircon also draws moisture from the surrounding air. The moisture cools when it touches the evaporator coil, forming tiny water droplets. The water then collects in the drain pan and drains outside through the drainage pipe as part of the aircon’s normal operation.
Water enters the room when it cannot drain correctly or when condensation forms outside a poorly insulated pipe. Identifying the source is important because each cause needs a different solution.
Common Causes of Aircon Water Leakage
1. Blocked Aircon Drainage Pipe
Water often leaks from an indoor aircon unit when its drainage pipe becomes clogged. Over time, dust, dirt, and sticky residue can build up inside the pipe and restrict the water flow. When the passage becomes narrow or completely blocked, condensation cannot flow outside. It backs up towards the indoor unit and eventually overflows.
Possible signs include:
- Water dripping below the fan coil
- A damp or musty smell
- Bubbling sounds near the drain connection
- Leakage starting after the unit runs for some time
- A little water coming from the outdoor drain outlet
A technician can vacuum or flush the pipe and check whether water flows freely. A drainage test is important because clearing only part of the blockage may result in another leak later.
2. Dirty Air Filter
A dusty filter restricts airflow through the indoor unit. As a result, the evaporator coil may become too cold, causing ice to form on its surface.
When the ice melts, the drain pan may not hold all the water. The excess then drips from the indoor unit.
However, filter cleaning alone will not solve the issue if dust has already reached the cooling coil, blower or drainage pipe.
Regular aircon servicing in Singapore can help remove dirt before it affects cooling and drainage.
3. Dirty Evaporator Coil or Blower
Fine dust can pass through the filter and collect on the evaporator coil, blower wheel, and drain pan.
Dust covering the coil can restrict airflow and cause ice to form. Some of this dirt may also wash into the drainage pipe, where it can build up and block the water flow.
The suitable cleaning method depends on the condition of the aircon. Light buildup may require general servicing. Heavier contamination may need an aircon chemical wash or aircon chemical overhaul.
4. Frozen Evaporator Coil
Freezing may happen because of:
- A clogged filter
- Restricted airflow
- A dirty evaporator coil
- A weak fan motor
- Low refrigerant
- Refrigerant leakage
- A sensor or control fault
If you see ice, switch off cooling mode and let it thaw naturally.
Arrange professional troubleshooting if freezing happens again. Wiping away the melted water will not correct the underlying problem.
5. Cracked or Misaligned Drain Pan
The drain pan catches water from the evaporator coil and directs it into the drainage pipe.
An ageing pan can crack, corrode, or move out of position. Its connection may also become loose. Water then escapes before reaching the drainage pipe.
Cleaning cannot repair a damaged pan. Depending on its condition, the technician may need to reposition, seal or replace it.
6. Damaged Pipe Insulation
Wet trunking does not always mean that water is overflowing from the fan coil.
Aircon refrigerant pipes are insulated to stop moisture from forming on their cold surfaces. When the insulation becomes thin, damaged, or poorly joined, humid air reaches the cold pipe surface. Water then forms outside the pipe and may drip inside the trunking, wall, or false ceiling.
Common signs include:
- Damp aircon trunking
- Water stains along the wall
- Dripping from a ceiling corner
- Moisture around pipe joints
- Leakage even when the indoor unit is clean
Singapore’s humid climate can make damaged insulation more noticeable.
7. Incorrect Drainage-Pipe Gradient
An aircon drainage pipe needs a consistent downward slope so water can flow out by gravity.
Water may remain inside a pipe that is level, bent upwards, or poorly supported. This can cause slow drainage, repeated blockages, and water flowing back towards the indoor unit.
A gradient problem may be suspected when the aircon started leaking after installation, continues leaking after cleaning, or uses a long concealed drainage route.
Correcting the piping arrangement may provide a better solution than repeatedly flushing the same pipe.
8. Loose Drainage Connection
The drain hose near the fan coil may become loose because of vibration, ageing, renovation work, or previous servicing.
Water may begin dripping as soon as the aircon produces condensation. The pipe should be reconnected, secured and tested before the unit is used again.
9. Faulty Condensate Pump
Some ceiling cassette, concealed and ducted systems use a pump to remove condensation.
If the pump is blocked, loses power, or fails, water can collect in the drain pan and overflow. The technician may need to inspect the pump, float switch, wiring, and drainage route.
10. Improper Installation
A newly installed aircon may leak because of poor fan coil positioning, unsuitable drainage gradient, loose connections or incomplete insulation.
Contact the installer if the problem begins shortly after installation. Ask for the drainage and insulation work to be checked under the applicable workmanship warranty.
Proper aircon installation in Singapore can reduce the risk of recurring drainage and condensation problems.
Aircon Leakage Symptoms and Possible Causes
| What you notice | Possible cause | Recommended action |
| Dripping below the indoor unit | Blocked drainage pipe | Switch off and arrange a drainage check |
| Ice on the coil or copper pipe | Airflow or refrigerant issue | Allow it to thaw and request diagnosis |
| Wet aircon trunking | Damaged insulation | Inspect the piping and insulation |
| Leakage after servicing | Loose connection or remaining blockage | Contact the servicing company |
| Leaking together with weak cooling | Frozen coil or dirty system | Arrange troubleshooting |
| Musty smell and dripping | Stagnant water or dirt buildup | Inspect the drain pan and pipe |
| Ceiling cassette dripping | Drain-pump problem | Arrange a cassette-unit inspection |
| Leakage after several hours | Slow drainage or condensation | Test the drainage flow |
Water can travel along trunking, piping, or a false ceiling before becoming visible. Therefore, the place where it drips may not be the source.
Can You Continue Using a Leaking Aircon?
It is safer to stop using the affected unit until the problem is checked.
Keeping it on produces more condensation and may increase the leakage. Even a slow drip can damage paint, plaster, timber flooring, furniture, and electrical equipment.
Stop using the aircon immediately when:
- Water is near an electrical point
- The leakage becomes heavy
- Water is entering a wall or ceiling
- Ice is visible inside the unit
- The aircon is no longer cold
- You hear unusual mechanical sounds
- There is a burning smell
- The circuit breaker trips
Do not touch a wet power point or switch. Seek qualified assistance when electricity may be involved.
Which Service Can Fix the Leak?
The correct solution depends on what the technician finds.
| Cause | Possible solution |
| Light dirt buildup | General servicing |
| Blocked drainage pipe | Drainpipe vacuuming or flushing |
| Dirty coil and blower | Chemical wash |
| Severe internal buildup | Chemical overhaul |
| Damaged insulation | Insulation replacement |
| Incorrect pipe gradient | Drainage correction |
| Cracked drain pan | Repair or replacement |
| Faulty drain pump | Pump repair or replacement |
| Frozen coil | Airflow and refrigerant diagnosis |
| Loose drain connection | Reconnection and testing |
A proper diagnosis prevents you from paying for work that does not address the source. Aircool’s aircon repair service can check maintenance-related and mechanical causes.
Why Is Aircon Leakage Common in Singapore?
Air conditioners in Singapore often operate for several hours every day. Bedroom units may run throughout the night, while office systems can remain on much longer.
During operation, the system continuously removes moisture from humid indoor air. Over time, dirt may build up inside the drain pan and pipe. Ageing insulation may also become less effective.
Pipes concealed inside trunking, walls or ceilings make the source harder to locate. Water may travel along the piping before appearing elsewhere.
Why Does the Leak Return After Servicing?
Recurring leakage may mean the original problem was not fully resolved.
The drainage pipe could still be partly blocked. There may also be damaged insulation, incorrect pipe gradient, a loose connection, a cracked drain pan, a freezing coil or a faulty pump.
Ask the technician to trace where the water begins. Repeating the same cleaning service without checking the complete drainage and piping system may provide only temporary results.
Does Low Aircon Gas Cause Water Leakage?
Low refrigerant does not normally appear as visible water. However, it can cause the evaporator coil to freeze.
When the ice melts, the drain pan or a partially blocked pipe may overflow. Do not request an aircon gas top-up based only on dripping water. The coil, airflow, and refrigerant pressure should be checked first.
How Can You Prevent Another Leak?
You can reduce the risk by:
- Cleaning washable filters regularly
- Arranging servicing according to usage
- Keeping the outdoor drain outlet clear
- Checking damp trunking early
- Not ignoring ice, smells, or unusual sounds
- Asking for drainage-flow testing after servicing
- Replacing worn pipe insulation
- Maintaining commercial units more frequently
An aircon maintenance contract may be helpful for units used frequently.
Need Help With an Aircon Water Leak?
Aircool Aircon can inspect the filter, coil, blower, drain pan, drainage pipe, insulation, and drain pump to identify the source of the problem.
For faster assistance, send us:
- Your location
- Aircon brand
- Number of affected units
- Where the water appears
- Whether the unit is still cold
- A clear photo or short video
WhatsApp Aircool Aircon: +65 9005 0975
Frequently Asked Questions
Why is my aircon leaking water?
The likely causes include a blocked drainpipe, dirty filter, frozen coil, damaged drain pan or worn pipe insulation. An inspection is recommended if the source is unclear.
Should I switch off a leaking aircon?
Yes, especially if the dripping is heavy or water is near electricity. Switching it off prevents the unit from producing more condensation.
Can normal servicing stop the leak?
It may help when light dirt or a minor blockage is responsible. Piping, insulation, drain-pan, and pump problems require different repairs.
Why is my aircon leaking but still cold?
Cooling and drainage are separate functions. The unit can remain cold while a blocked pipe or damaged drain pan allows water to overflow.
Is aircon water leakage dangerous?
The water is usually condensation, but it can damage walls, ceilings, flooring, and electrical equipment. Persistent dampness may also encourage mould growth.
How much does aircon leak repair cost?
The cost depends on the cause, accessibility, and work required. Request a clear diagnosis and quotation before approving the repair.
