Why AirCon Leaking Water ?

It must be frustrating when your aircon leaking water. When it happens, the first thing that most people do is to put a bucket below the leaking air-con and call for an air-con service for help. Not long after servicing the air con, it started leaking again! Have you ever wonder what really is the root of the problem? Is it really because your air conditioning units are just dirty? You are half right when you say that but there are more reasons to it. Let us look into what is the top 3 reasons that cause your aircon leaking water.

Possible Reasons Why Your Aircon Leaking Water

# 1 - Coil fin & Drainage tray clog with dirt

When your air conditioning units is switched ON, it will bring the outdoor air to the air-con unit and convert the air into cool air. During this process, the outdoor dust will be stuck onto the coil fin. The dust will mix with the water in the coil fin, forming “dirt”. This dirt will then flow through the drainage pipe from the indoor air-con unit to the toilet. When there is too much dirt forming in the drainage pipe, it will start to clog and water will start to flow out from the indoor air-con instead.

aircon coil fins and drainage tray stucks with dirtaircon coil fins and drainage tray stucks with dirt

As you can see from the image above, the coil fins and drainage tray was stuck with dirt during.. Without much maintenace , your aircon will clog with dirt leading to water leaking issue and drop of cooling efficiency. A Chemical Aircon Servicing is need which will help to wash out all the dirt formed in the fin coil and clears the drainage tray.  

Doing your own maintenance by keeping your room dust-free and cleaning of air con filters will help to reduce the amount of dust sticking onto the air-con coil fin. This will prevent the dirt from building up too quickly.

#2 - Drainage pipe has no gradient

When your air-con is switched ON., condense water will start to flow from the fan coil to the toilet through the drainage pipe. Many air-con installers tend to install the drainage pipe too horizontally thus causing the drainage pipe to clog easily. It is better for the drainage pipe to be installed slightly slanted to allow the water to flow through the drainage pipe smoothly hence helps to push the dirt out.

#3 - Drainage pipe is too long

Do you realize that the air conditioning units that is located furthest from the toilet, where the drainage pipe drains away the water, usually leaks more often? Drainage pipe is usually installed in such a way that the main drainage pipe to the toilet will be shared among all the air-conditioners units. When all of your air-con is switched ON, dirt will formed at the main drainage pipe which caused the furthest air con to leak more often.

There are two ways in solving this problem. One way is to change the drainage pipe to a bigger diameter, this will minimize the possibility of it being clogged up.. Another way is to install an additional drainage pipe for the air-con.


After stating the top 3 reasons of aircon leaking water above, you might realize that beside Problem #1, caused by daily usage, the rest are caused by improper installation. The installation phase is important and improper installation will cause the air-con to leak often at the later stage. Get a licensed air-conditioning company to do a proper installation for you! 

If you are keen in doing your own air-con cleaning by yourself do check out this blog.

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