Air conditioner leaks generally occur because of a hole in the overflow pan, an air filter clog or a plugged condensate line. To fix the leak, identify the cause and take the necessary steps to repair it.
Check for holes in the overflow pan
Overflow pans are designed to catch drainage from the air conditioning unit. Holes in the pan result in a slow trickle of water. Check the ground around the unit. Trace any leaks back to the source. Inspect the overflow pan in the vicinity of the leak for holes. Use a flashlight if necessary. Small holes can be plugged with epoxy. Large holes require the purchase of a new overflow pan.
Look for clogs in the air filter
Dirty filters cause ice to form on the evaporator coils. Melting ice could be the source of the leak. Replace the filter. Change the filter every month when the unit is in use to prevent the problem.
Examine the condensate line
The condensate line is a pipe that runs from the overflow pan to the ground. It is designed to drain the pan. Sometimes this line becomes clogged, resulting in water building up in the pan. The pan will eventually flow over the brim, causing the water leak. Use a wet/dry vacuum or a hand pump to blow the line clear.