Aircon Water Dripping? 5 Causes and How We Fix Them

Aircon dripping water onto your floor (or worse, your bed) is one of the most common emergency calls we get. Good news — it's usually fixable in under an hour, and it's almost never the doomsday scenario you fear. Here are the 5 causes ranked by how often we see them.

1. Clogged drain pipe (60% of cases)

The most common cause by far. Dust + mould + bacteria build up in the drain pipe over time, eventually blocking it. Water that should drain outside backs up into the indoor unit's drain pan and overflows onto your floor.

Fix: A technician uses a vacuum or nitrogen blower to clear the line. Takes 15–30 minutes. Cost: $30–$60 callout. Often included in a regular service if caught early.

2. Drain pipe slope wrong / kinked (15% of cases)

Water needs gravity to flow out. If the drain pipe was installed without enough slope (sometimes happens during sloppy initial installation), water sits and eventually overflows. Also happens if furniture was pushed against a kink in the pipe.

Fix: Re-route the pipe with proper downward slope. $80–$150 depending on length and access.

3. Drain pan cracked or rusted (10% of cases)

After 7–10 years, the plastic drain pan inside the unit can crack — water leaks INSIDE the unit before it reaches the drain pipe.

Fix: Replace the drain pan ($60–$120 depending on model). For units 10+ years old, sometimes more cost-effective to replace the whole unit if other parts are wearing out too.

4. Frozen coil → melts → overwhelms drain (10% of cases)

If your coil iced up (from low gas or restricted airflow), then as it melts, it dumps more water than the drain pan can handle quickly enough.

Fix: Address the underlying cause (clean filters, top up gas, fix leak) — then the dripping stops naturally.

5. Refrigerant leak — water on outdoor unit (5%)

Less common but distinct: if you see water dripping from the OUTDOOR unit, not the indoor, it's usually a refrigerant leak at the flare nut joint causing condensation.

Fix: Pressure-test to find the leak, tighten or replace the flare connection, top up. $60–$150.

Quick test you can do now

Turn off the aircon and dry the surroundings. Then turn it back on and watch carefully for 30 minutes:

• Dripping starts within 5–10 min → clogged drain or wrong slope
• Dripping starts after 20+ min → likely frozen coil, low gas issue
• Visible ice on the indoor coil through the louvre → frozen coil confirmed
• No dripping at all but you saw water earlier → likely a one-off (clogged drain that cleared itself)