If your aircon is dripping water inside your home — onto the floor, down the wall, or out of a ceiling vent — you're not alone. In Brisbane's humid summers, indoor leaks are the single most common service call we get. The good news: it's rarely "broken." It's usually fixable. Here's what's actually happening, in plain English.

First, turn it off. If water is actively dripping, switch off the unit at the wall. Running it while it leaks risks electrical damage to the indoor PCB or ceiling water damage if it's a ducted return.

How aircons normally handle water

Air conditioners pull humidity out of your home's air. That moisture condenses on the cold indoor coil, drips down into a small drain pan, and runs out a thin drain pipe to the outside of your house. When the system works, you never see a drop indoors.

When the system doesn't work, that water has to go somewhere. And "somewhere" is usually your floor or ceiling.

The 5 reasons your aircon is dripping inside

1. Blocked condensate drain line (60% of cases)

The most common cause by a wide margin. In Brisbane, that thin drain pipe clogs with mould, algae, and dust within 12-18 months. When it clogs, water backs up into your drain pan and overflows.

How to spot it: Look outside for the drain pipe (usually a small white or grey pipe about pencil-thick). If no water is dripping out of it while the AC is running, it's blocked.

DIY fix (10 mins): Get a wet/dry vacuum and put it over the outdoor end of the drain pipe. Run it for 60-90 seconds. If you're lucky, it'll suck the blockage out. Doesn't always work for fully-cemented mould plugs — those need flushing.

2. Filthy filter

A dirty filter restricts airflow. Low airflow makes the indoor coil too cold, ice forms, then when it melts the drain pan overflows. Filter cleaning is supposed to be monthly. Most Brisbane homes do it once every two years if ever.

DIY fix: Pop the front cover, pull the mesh filter, vacuum it then wash with mild soap, let it dry fully, put it back. Run the AC. If the leak stops within an hour, that was it.

3. Frozen indoor coil

Caused by low refrigerant (gas leak — needs a tech), restricted airflow (dirty filter or blocked vents), or running the AC too cold for too long. The coil freezes solid, then melts and overflows the drain pan.

How to spot it: Open the front cover with the AC OFF. If you see white ice on the coil, that's your problem. Leave the unit off for 2-3 hours to fully thaw, then run only on Fan mode for 30 mins to dry it out before testing again.

4. Drain pan rusted through or cracked

Older systems (10+ years) sometimes develop holes in the metal drain pan from years of humidity. Water bypasses the pan entirely and drips onto your wall or ceiling.

DIY fix: None — needs a tech to assess and replace.

5. Bad install / not enough fall on the drain line

If the AC was installed level, water won't flow out. The drain line needs at least a small downhill slope. Rare problem in established homes, more common after a renovation or DIY install.

DIY fix: None — the drain line geometry needs fixing.

Why this keeps happening in Brisbane

Brisbane runs hot and humid for 6+ months a year. That means:

Your aircon pulls a LOT of water out of the air (way more than Sydney or Melbourne)
That drain pipe stays damp year-round — perfect for mould + algae growth
Filters trap more dust because the AC runs more hours
The "every 12 months" cleaning advice that works in cooler climates isn't enough here — 6-9 months is closer to reality for Brisbane

When to call a pro

Call us if:

You tried the DIY drain flush and it's still leaking
You see ice on the indoor coil that doesn't thaw with the unit off
The unit is older than 8 years and the drain pan looks rusty
Water is coming out of a ceiling vent (ducted system) rather than the indoor unit itself
You smell musty / mouldy when the AC runs

Our drain flush + clean service

$89 covers a full filter clean, drain pan + line flush, coil inspection, and a clear answer on whether it's fixed or needs more work. No call-out fee.

Call 0483 981 381

The honest answer

If your aircon is dripping water, 90% of the time it's a blocked drain line and you can probably fix it with a vacuum in 10 minutes. The other 10% — frozen coil, cracked drain pan, gas leak — needs a tech. We'll come out, diagnose for free, and tell you straight if it's a DIY job or worth our time. No upselling. That's the only way we know how to do this.