Air Conditioners Water Accumulating in Base Pan

As warm moist (humid) air from the room passes over the cold indoor coil, water condenses on the cold indoor coil and collects in the base pan where it flows to the rear of the unit.

Water will collect in the base pan and may even overflow and drip outside during periods of high humidity or on rainy days. This is normal operation.

Most room air conditioners do not have a drain plug to drain the water. Air conditioners have a "slinger ring" around the rear fan blade. The ring is designed to pick water up off the bottom of the pan and throw it against the condenser coils. This design feature helps improve the efficiency of the unit by reducing heat on the coils, and helps remove some of the moisture from the pan.