If you believe you have heard or seen water leaking form your air conditioner unit you could potentially have a very serious problem on your hands. The larger coil unit will most likely be installed in the attic or in a closet. You should immediately check that area for drainage, or freestanding water. If there is evidence of an air conditioner leak you should turn the AC unit off immediately.

The outdoors compressor fan will have copper tubing running into the home. Touch the copper tubing and see if it feels frozen. If so your coils have most likely frozen and their thawing has lead to the leak. Assuming the coils and tubing do not indicate freezing, there are some other items to be checked.

Every AC unit has a coil drip pan which will catch any over flow water from the unit. There is a possibility that this pan could be cracked. If so replacing the pan is relatively cheaply done. Most likely you will not need to purchase new coils. Also, an appropriate epoxy glue may be able to seal a cracked drip pan.

Most pans come equipped with an overflow shutoff valve. It is feasible that this valve is not being tripped for some reason. If the valve is broken you may need to call a technician to replace it. Otherwise you might be able to assume that the pan is tilted in such a way that the valve is not being tripped. This would most likely be caused by recent work on or around the unit.