Why is your aircon leaking water and how to fix it

Picture this: it’s 35 degrees outside, you’ve got the aircon running… but now it’s leaking all over your floor. It’s a true blue Aussie nightmare. If you’ve spotted water pooling under your unit or noticed a steady drip from your split system, don’t ignore it. A leaking air conditioner might seem like a minor annoyance, but leaving it for too long can lead to water damage, mould growth, and even structural issues. 

It will also impact your air conditioning efficiency, costing you more in power bills and comfort. Let’s break down why your air con is leaking, how to fix it, and when to call in a pro. In this article, we'll cover: 

• Why is your air conditioner leaking water?

• Can you still use an air con if it's leaking?

• When should I call a professional for an aircon water leak?

• How to fix a leaking air conditioner

• How much does air conditioner leak repair cost?

• Is professional air con repair for leakage worth it?

• How to prevent your air con from leaking

• How to find an air conditioning service near you?

Why is your air conditioner leaking water?

If you’re wondering why your aircon is dripping or leaking water, then there are likely a few causes:

• Blocked or clogged drain line: The most common culprit of an aircon dripping water. Dust, dirt, and mould can clog the line that drains condensation away from the unit causing leaks
  Dirty air filter: When filters get too grubby and gross, airflow is restricted causing the evaporator coils to freeze. When they thaw, water then spills over and voila! a leaking aircon unit. Never skip the air conditioning filter cleaning

• Cracked or rusted drain pan: The drain pan is there to collect condensation. If it’s damaged, water won’t stay where it should and this can lead to your air conditioner leaking water inside

• Low refrigerant levels: This can also lead to freezing coils and water overflow when the ice melts

• Faulty condensate pump: In systems that rely on a pump to remove condensation, a breakdown means water has nowhere to go

Can you still use an air con if it's leaking?

Technically, yes you can still use an air conditioner if it’s leaking water. But you shouldn't. Using your air conditioner while it is leaking can quickly make the issue worse. Water can damage electrical components or your walls, ceiling, and flooring. We highly recommended turning it off and investigating the source of the issues before running it again.

When should I call a professional for an aircon water leak?

If you’ve tried the basics and there is still water leaking from the aircon, or if you’re not sure what’s causing the problem, it’s time to bring in a tradie. Other times where it’s best to hire a professional include: 

• If you see ice forming on the unit, as this could indicate a refrigerant issue that only a qualified technician is legally allowed to handle 

• If you 

• The leak keeps coming back

• There’s a musty smell or visible mould

• Water is near electrical components

Some repairs require a licensed technician by law, and they’ll have the tools and experience to get the job done properly.

How to fix a leaking air conditioner

If you’re handy and the issue is minor, you might be able to sort it yourself. But if you’ve tried and there is still water coming out of the aircon then we’d always recommend calling in a pro. And if the issue is refrigerant related you’ll 100% need a trusted tradie for the job. 

But if you do want to try and stop the water leakage yourself, try:

• Turning off the unit to prevent further damage

• Cleaning up any water using a towel or wet/dry vacuum

• Checking the drain line for blockages—this is one of the most common causes and can often be fixed by clearing the line with a vacuum or plumber’s snake

• Checking and replacing the air filter if it’s dirty, as poor airflow can cause freezing

• Inspecting the drain pan for any rust or cracks—if it’s damaged, patch it or replace it

• Looking for ice on the evaporator coils, as this could point to restricted airflow or low refrigerant

If you have a condensate pump, it’s a good idea to also check it for unusual noises or blockages. If you can’t pinpoint the issue or suspect the issue might be refrigerant-related, it’s time to bring in a professional. 

Read more: Air conditioning maintenance checklist 

How much does air conditioner leak repair cost?

Air conditioning repair costs vary depending on the nature of the repair itself. However, expect to pay anywhere from $70 to $150 if it’s a simple filter change, $160 - $400 if it's a refrigerant change, or $250 - $1,600 if it turns out to be something more serious.  

Remember, if you don’t get it fixed you’re not only risking more damage but could also be paying more for your air conditioner to run. 

Related articles: How much does aircon cost to run?

Is professional air con repair for leakage worth it?

Getting your air con repaired professionally is absolutely worth it. While DIY is fine for cleaning and minor fixes, but more complex issues like refrigerant problems, pump repairs or recurring leaks are best left to the experts. Getting it fixed properly can save you money long-term, prevent water damage, and keep your unit in top notch working condition.

How to prevent your air con from leaking

Air conditioning leak prevention is the way forward. And that means regular air conditioning maintenance, including:

• Booking a yearly service with a qualified tech to keep your unit running smoothly (with no pesky leaks)

• Checking and changing your filters monthly—or at least every 1–3 months, depending on use. Air conditioning cleaning is important

• Clearing the drain line every few months with a vinegar and water flush

• Not setting your thermostat too low—extremely low settings can increase condensation and freezing

• Making sure windows and doors are closed while the air con is running to reduce indoor humidity

The cost to service an air conditioning unit is between $75 - $200. Regular cleaning and servicing can help you avoid more expensive air conditioner repair costs, which can be anywhere from $70 - $2,500 depending on how serious the problem is. 

Find an air conditioning service near you

A leaking air conditioner might seem like a small problem, but it’s usually your unit's cry for help. If you ignore it, it’s likely only to get worse (and more expensive). Acting quickly, keeping up with regular maintenance, and knowing when to call in the pros will keep your system running smoothly, efficiently, and drip-free.