The most common cause of a leaking aircon in Singapore is a choked condensation line. Dust and humidity feed a slimy algae "jelly" that silts up the drain over months, so condensate overflows the tray instead of draining away. A quick filter rinse helps, but jelly deep in the pipe usually needs a pressurised flush.
If the filter is dirty, the evaporator coil freezes. When it melts, it overflows the drip pan.
Low gas causes the system to freeze up. You will need a professional technician to top up the gas and seal the leak.
Older units (over 5-7 years) can develop a rusted or cracked drip pan, so water escapes even when the drain is clear. This usually shows up as stains directly under the fan coil and needs the tray replaced — price is confirmed on site after the technician assesses the unit.
If rinsing the filters does not stop the drip, the jelly is sitting deep in the drainage pipe and needs a professional chemical wash with a pressurised flush — typically from S$90 per fan coil (indicative). A FixMove technician can clear the line, check the drip tray and confirm the price before any work starts.
First 10 Minutes: What To Do Before the Water Spreads
A dripping fan-coil unit can soak a false ceiling, warp skirting and short the wall-mounted PCB within hours, so act fast. Switch the unit off at the wall isolator (not just the remote) to stop the coil cooling and producing more condensate. Place a towel and a basin under the drip, then wipe the wall dry. In an HDB or condo bedroom the drainage usually runs to a floor trap or out through the wall via a slope pipe — if water is coming from the unit face instead of the outlet, the drain is almost always blocked downstream.
While the unit is off, gently lift and rinse the front filters under a tap (most Singapore units have two slide-out mesh filters per fan coil). A clogged filter is the single most common DIY-fixable trigger here because our humidity loads the coil with condensate around the clock.
Should You DIY or Call a Pro?
Safe to DIY: washing the filters, wiping the drip tray you can reach, checking that the outdoor drain pipe outlet is not blocked by debris, and confirming the unit is mounted level (a tilted fan coil sends water to the wrong side of the tray). These need no tools and no gas handling.
Call a professional when: the drain is choked with the slimy algae "jelly" deep in the pipe, ice forms on the copper pipes, the unit hisses or cools poorly (a sign of low refrigerant), or the drip tray is rusted and cracked. Pressurised drain flushing, vacuum pump-out and gas work all require a trained aircon technician — in Singapore, refrigerant handling should be done by an experienced servicing crew, not a homeowner.
Symptom → Likely Cause → Fix & Indicative Cost
| What you see |
Likely cause |
Fix & indicative SG cost |
| Steady drip from unit face |
Choked condensate drain ("jelly") |
Drain flush / chemical wash, from S$90 per fan coil (indicative) |
| Ice on copper pipes, weak cooling |
Dirty filter/coil or low refrigerant |
Chemical wash from S$90; gas top-up typically S$80–S$160 |
| Water only on one corner |
Fan coil mounted off-level |
Re-level / re-bracket, from S$80 (indicative) |
| Stains under unit, old system |
Rusted / cracked drip tray |
Tray replacement, price confirmed on site after assessment |
Prices are indicative only and confirmed by your FixMove coordinator or on-site technician after assessment. See the full FixMove price list for all aircon jobs.
Stop It Coming Back
In Singapore's year-round humidity, fan coils run hard and drains silt up fast. The simplest prevention is a routine service: rinse filters every 2–4 weeks if you run the aircon nightly, and book a chemical wash for the drain and coil roughly every 3–4 months for heavy use (or twice a year for light use). A clean drain line almost never overflows. For wider servicing, gas and installation help across all estates, see the FixMove aircon hub.
FAQ
Is a leaking aircon dangerous or just messy?
It is condensation, not refrigerant, so the water itself is harmless. The risk is water damage to ceilings, walls and the unit's electronics, plus mould in HDB/condo bedrooms. Switch it off at the isolator and dry the area until it is fixed.
Can I clear a choked aircon drain myself?
You can rinse filters and clear debris at the outdoor pipe outlet. But the slimy algae "jelly" usually sits deep in the line and needs pressurised flushing or vacuum pump-out, which is part of a professional chemical wash from S$90 (indicative).
How often should I service my aircon in Singapore?
Rinse filters every 2–4 weeks for nightly use, and do a chemical wash roughly every 3–4 months for heavy use or twice a year for light use. Our humidity loads coils and drains far faster than temperate climates.
Why does my aircon leak only when it is very humid or raining?
Higher humidity means the coil produces more condensate, so a half-blocked drain that coped on dry days overflows on wet ones. It is an early warning that the drain line needs flushing before it chokes fully.