Why is my aircond leaking water inside the house?

The most common cause in Malaysia is a drain line blocked by biofilm and algae sludge. Condensate backs up in the drain pan and overflows into the room. Other causes: a heavily soiled coil that ices up and melts, a cracked or tilted drain pan, or an installation without enough drainage slope.

Is a leaking aircond dangerous?

The water itself is condensate, not refrigerant, and is not hazardous — but continuous dripping damages walls, ceilings and furniture, and standing moisture encourages mould. If water reaches electrical parts or the unit trips the breaker, switch it off and call a technician.

How much does it cost to fix a leaking aircond in KL?

If the cause is a blocked drain or dirty coil, a chemical wash with drain flush from RM130 per wall-mount unit fixes most cases. A repair visit for diagnosis is RM100 per call. Cracked drain pans or re-sloping drain piping are quoted after inspection.

Can I fix a leaking aircond myself?

You can safely check and clean the filter, and check whether the drain pipe outlet outside is dripping freely. Do not open the unit body or pour chemicals into the drain line yourself — incorrect handling bends coil fins and can push the blockage deeper.

Troubleshooting · Repair

Aircond Leaking Water? Causes and How to Fix It

Written and reviewed by the Mavis Eco Cool service team — the technicians who do this work daily across KL & Selangor. Published 2026-07-15.

Water dripping from the indoor unit is one of the most common aircond complaints in Malaysian homes — and one of the most damaging if ignored, because it stains ceilings, warps cabinets and feeds mould. The good news: in most cases the cause is simple, the fix is quick, and you can narrow it down yourself before anyone touches the unit.

By Mavis Eco Cool · Published 15 July 2026

Cause 1: Blocked Drain Line (the usual suspect)

Your aircond constantly pulls humidity out of the air. That water collects in the drain pan under the evaporator coil and flows out through a small drain pipe. In Malaysia's warm, humid climate, that constantly-wet pipe is a perfect home for biofilm and algae — a jelly-like sludge that slowly narrows the pipe until water backs up and overflows into the room.

How to identify: Dripping starts gradually and gets worse over days or weeks. The unit still cools normally. Outside, the drain outlet drips slowly or not at all even while the unit runs.

Fix: A drain line flush — done properly as part of a chemical wash (from RM130 per wall-mount unit) which also removes the sludge source from the pan and coil, not just the pipe. This resolves the large majority of leaking complaints we see.

Cause 2: Dirty Coil That Ices Up, Then Melts

A dust- and mould-coated evaporator coil restricts airflow. With too little warm air passing over it, the coil can drop below freezing and build a layer of ice. When the unit stops, the ice melts — often producing more water than the drain pan can handle at once.

How to identify: Leaking comes in bursts, typically after the unit has been switched off. Cooling is noticeably weaker. You may see frost on the copper pipe or hear dripping inside the unit after shutdown. Weak cooling with icing has overlapping causes — our aircon-not-cold guide covers the full diagnosis.

Fix: Chemical wash to restore airflow across the coil. If icing continues after a proper wash, the refrigerant level needs checking (gas top-up with leak check from RM150).

Cause 3: Cracked, Rusted or Tilted Drain Pan

The drain pan itself can crack with age, rust through (older units), or sit slightly out of level after years of vibration — letting water escape before it reaches the drain hole.

How to identify: Dripping from one specific corner of the unit, often even when cooling load is light. More common on units eight years and older.

Fix: Pan repair or replacement, quoted after inspection (repair visit RM100 per call, deducted from the repair if you proceed with us).

Cause 4: Installation Problems — No Drainage Slope

Condensate drains by gravity. If the drain pipe was installed with too little fall — or with a sag in the middle where water pools — the system leaks from day one or starts leaking once slight sludge builds up in the low spot.

How to identify: A newer unit that has leaked from early in its life, or leaking that returns quickly after every flush.

Fix: Re-routing or re-sloping the drain pipe. If you are planning a new installation, this is exactly why proper commissioning matters — our installs include a drainage test before handover.

Cause 5: Cassette Units — Failed Drain Pump

Ceiling cassette units in shoplots and offices use a small pump to lift condensate up into the ceiling drain. When the pump fails or its float switch jams, water overflows through the ceiling grille — usually onto a desk or counter below.

How to identify: Cassette unit dripping through the grille or ceiling boards staining around the unit.

Fix: Pump or float switch replacement, plus a cassette service (RM350) if sludge caused the jam — sludge is usually why the float sticks.

What You Can Safely Check Yourself

Before booking anyone: rinse the filter (dirty filters make Causes 1 and 2 worse), look at the outdoor drain outlet while the unit runs (a healthy system drips steadily), and note WHEN it leaks — continuous dripping points to the drain line, dripping after shutdown points to icing. Tell the technician these three things and you shorten the diagnosis.

Do not open the unit casing, poke wires into the drain pipe, or pour bleach or chemicals into the drain line. We regularly repair damage from DIY drain-clearing attempts that pushed the blockage deeper or cracked the pan.

When to Call a Technician

Call the same day if: water is reaching electrical trunking or a power point, the breaker trips when the unit runs, or the ceiling below a cassette unit is staining. Otherwise, book a normal slot — but do not run the unit with a towel underneath for weeks; the moisture damage usually ends up costing more than the fix.

For KL & Selangor, WhatsApp 019-221 7190 with a photo or short video of the leak — it usually tells us the cause before we arrive. Same-day slots are common if you message before noon.

Sources

Daikin Malaysia — owner's manual maintenance guidelines for split air conditioners
Panasonic Malaysia — split aircon troubleshooting documentation
Mavis Eco Cool service-call patterns across KL & Selangor (2026)