Why is my aircon leaking water?

There are a few reasons that why your aircon might be leaking,

1. The gradient of the drain pipe is insufficient, thus causing water to flow slowly or even causing the water to get stagnant along the pipe. This will cause jelly to build up and then later cause a back flow of condensate out from your indoor unit.
2. Your indoor unit is not tilted slightly to allow water from the drain pan to flow out to the drain pipe. In the long run when your drain pan is stuck with jelly and dirt, it will cause a overflow from your indoor unit.

If you experience this problems frequently, the only way is to get servicing done regularly to keep the drain pan and drain pipe clean so as to allow water to flow out smoothly. You may also use a clear choke tablet and place it in your drain pan so this would allow it to prevent forming of jelly.