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Why is my Aircon Leaking Water?

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Why is my aircon leaking water?

It is almost a necessity to have a working air conditioner in a climate like Australia’s. If you have an air conditioning unit in your home, chances are, you’ve asked yourself “why is my aircon leaking water?”. There are many reasons why your air conditioner unit might leak. From a clogged drain line to a damaged condensate pump. The good news is though, most of these leaks can be prevented with proper maintenance.

At Glenco, we’ve been looking after Sydney’s air conditioning systems for many years! In this article, we discuss the answer to the question, “why is my aircon leaking water?”.

Why is my aircon leaking water?

An air conditioning unit will always produce moisture due to an evaporator coil. The coil works to cool the hot air that blows out of the unit, and as a result, the coil forms condensation. There are several ways AC units can capture the moisture, but without proper maintenance, they may fail.

Let’s take a closer look: 

Clogged condensate drain line

The water produced by the evaporator coil drops into a drain pan, which flows into a drain line. The drain line redirects water to the outside of your house, typically near the AC ventilation system. The drain line is usually made from PVC pipe, which can become clogged by dirt and debris. Mould and algae can also form inside the drain line due to the levels of moisture. 

Once the drain line is blocked, the excess condensation builds up and can cause the drain pan to overflow. A clogged drain line is one of the most common reasons for an air conditioning unit to leak water.

Clogged air filter

A clogged air filter can cause a lot of issues for your AC system. When the air filter becomes dirty and blocked, it significantly reduces its airflow. The AC unit can overheat and stop producing cold air if the air filter becomes clogged. 

When the airflow is restricted, the evaporator coils won’t receive enough hot air, resulting in the coil freezing over. When the evaporator gets covered in ice, it can cause excess water to miss the drain pan and leak into your home. 

leaking air

Besides water leaking from your air conditioner, a clogged air filter can result in harmful and dirty air blowing into your home. The filters can become clogged with bacteria, mould and dirt that might find their way into your home. 

If an air conditioner is not properly installed and insulated, then ambient air can access parts of the unit filled with much cooler air. Condensation will form, and the water may drop from different places, where there is no container or pump to help redirect it. 

Damaged drain pan

Water that drips from the evaporator coil ends up in a container. Attached to the container is a pump that leads water to the drain line. If the container is damaged and has holes, it can cause water to leak outside of the drain line. If your drain pan is damaged, then it likely needs replacing.

Most drain pans have a float switch that can sense when the container is about to overflow. The switch turns off the AC unit to prevent more moisture from forming. If this switch is damaged, your drain pan can continue to fill up. 

Low refrigerant

Refrigerant passes between all the major components of an air conditioner. The refrigerant is a substance that transitions between a gas and a liquid. It’s responsible for redirecting hot and cool air indoors and outdoors.

If your air conditioner is low on refrigerant, the evaporator coils won’t receive enough hot air, resulting in the coil freezing over. A leak in the refrigerant lines is likely to make a hissing sound due to the high pressure within. 

Refrigerant lasts a very long time, so if you are low, it may be due to a leak. In this case, you’ll need an air conditioner technician to fix the leaks, or you may need to replace your AC system. 

Dysfunctional condensate pump

The condensate pump is an integral part of air conditioning units. The pump is attached to the container that collects dripping water. Within that container is a switch that tells the pump how much water is being held. Once the water reaches a certain level, the condensate pump will activate, redirecting water to the drain pipe. 

If the pump does not register the levels of water, then it can fail to activate. The water continues to collect and eventually overflow, resulting in leakage. The part where the water exits the pump may also become blocked, which can cause the pump to shut off. 


If you’ve ever wondered, “why is my aircon leaking water?”, we hope we have shed some light on this for you. Having an air conditioner becomes an essential part of life when living in Australia. Whether you’re at home or working in a factory, having a comfortable temperature can make a world of difference. In some extreme cases, access to cool air may even save a life. Not only can old and damaged AC components cause water leakage, but they can also result in higher utility bills and dirty air circulating through your house. 

Glenco has a team of specialist air conditioner and refrigeration technicians. Experienced in the installation, service and inspection of air conditioners, our technicians have you covered. Whether it’s commercial or residential, Glenco is equipped and experienced to complete any job. 

Contact us, to find out how Glenco can help. 

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