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Aircon Leaking Water? The Causes in Order, and What Each Fix Costs

6 September 2026 by
Aircon Leaking Water? The Causes in Order, and What Each Fix Costs
By Aircon Hero Team5 min readUpdated 2026-09-06
A damp brown stain spreading across a peeling ceiling in the corner of a room with a bare pendant lamp, the mark an aircon leaking water leaves overhead.
Quick answer: An aircon leaking water is nearly always water the unit made itself and could not drain: a blocked drain line, a choked filter, or a pan out of slope. Aircon Hero's basic wall-mounted service, RM88 for one unit, includes drain pan and drain line cleaning, as listed on the Aircon Hero price list on 2026-09-06.

Is an aircon leaking water dangerous?

Water dripping from an indoor unit is not an emergency, but it falls close to live electrics. Switch the unit off at the isolator before opening any cover, put a basin under the drip and leave the casing shut. Leave the unit off until a technician has seen it, so the drain pan is not refilling while it drips.

The damage costs more than the fault: a slow drip stains plasterboard and, in a condo, reaches the neighbour.

What causes an aircon leaking water?

An aircon leaking water usually has one of four causes: a blocked drain line, a filter so dirty the coil ices over, a pan or pipe that has lost its slope, or low refrigerant. Klang Valley conditions push the first two up the list.

  1. A blocked drain line. Dust, slime and algae build up inside the condensate pipe, so the pan fills faster than it empties and spills.
  2. A dirty filter starving the coil. With airflow choked the coil frosts over, then melts in a rush when the unit stops and floods past the pan. Roadside dust loads filters fast; Aircon Hero recommends a residential service every 3 months.
  3. A pan or pipe out of slope. Condensate drains by gravity, so a sagged bracket or a flat run holds water.
  4. Refrigerant-related icing. A unit low on gas ices in patches and drips as it thaws, with weak cooling too: see why an aircon runs but is not cold.

Which leak symptom points to which cause?

Where the water appears narrows the cause faster than anything else. A drip from one end of the indoor unit points at drainage, frost anywhere points at airflow or refrigerant, and a wet patch behind the casing points at pipework.

Symptom Likely cause DIY or technician
Steady drip from one end of the unit Blocked drain line Technician
Water after hours running, then a rush Coil icing, thawing DIY: clean filters
Drip from mid or rear of the casing Pan out of slope Technician
Frost on the pipe, weak cold air Low refrigerant Technician
Wet wall at the pipe outlet Damaged lagging Technician

Cleaning the filters is the one step worth trying yourself. Do not spray anything inside the unit: Daikin Malaysia warns that commercial cleaning agents can cause "problems such as water leaks".

Is water dripping from the outdoor unit a fault?

Usually not. Daikin Malaysia's troubleshooting page states: "During cooling operation, the pipes in the outdoor unit become cold and may cause water condensation." Condensate from the indoor unit is piped outside by design too. Water pooling under the outdoor unit is normal; water in the room is not.

What does it cost to stop an aircon leaking water?

Aircon Hero charges RM88 to diagnose a non-inverter wall-mounted unit and RM108 for an inverter unit. A basic service is RM88 for one unit, RM78 each for two and RM68 each for three or more, covering drain pan and drain line cleaning, filter and coil cleaning, and a system test.

Where the pan and coil are badly fouled, a full chemical service on a wall-mounted unit is RM198, or RM168 and RM148 each for two and for three or more, with a 1-month service warranty from the date of cleaning. Leak fix and relocation are quoted after inspection.

Book the drain clean before the ceiling stains

Switch off at the isolator, then book an aircond service to clear the pan and drain line. If that does not stop it, book an aircon repair diagnosis. Figures are on the Aircon Hero price list, and the complete guide to aircond service in Malaysia covers a full visit. WhatsApp +60 18-355 5162 or email [email protected].

Frequently Asked Questions

Better not to. Every hour of running adds condensate a blocked system cannot drain, and the water lands near the indoor unit's electrics. Switch off at the isolator, catch the drip and clean the filters; if the leak returns, book a technician.

Often, yes. Aircon Hero's basic service on a wall-mounted unit includes drain pan and drain line cleaning alongside the filter and coil, so a routine blockage is usually cleared in that visit. A badly fouled pan or a slope problem needs more.

Condensate moves by gravity, so a drain run laid flat or bent upward holds water and backs it into the pan, and a bracket that is not level tips the pan the wrong way. Nothing inside is faulty; Aircon Hero quotes the re-set after inspection.

It starts as condensation from room air but does not stay clean. It runs over a coil and through a pan that collect dust, and picks up biofilm from the pipe, which is why a long-blocked drain smells sour. Wipe spills promptly.

Aircon Hero covers chemical cleaning with a 1-month service warranty from the date of cleaning, so a drainage problem returning inside that window falls under the warranty policy. That policy excludes compressor failure and gas leakage, and parts carry their manufacturers' warranties.

Aircon Hero services all major brands, including Daikin, Panasonic, Mitsubishi, Samsung, LG, Midea, Acson, York and Carrier, so the badge on the casing does not change how a leak is approached. Unit type sets the price: wall-mounted, cassette, ceiling exposed and ducted.

Sources: Troubleshooting - Daikin Malaysia (2025-09)

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Seven days a week across Klang Valley. Clear quote before any work, and a 1-month warranty on chemical cleaning.

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