Air Conditioner - Water Dripping Outside

It is normal for the base pan in an air conditioner to fill with water. This water comes from moisture collected as the air conditioner draws moisture from the indoor air. It also comes from collected rainwater. At some point, the base pan may be full enough for water to drip out of the back of the air conditioner. Window air conditioners should be installed with a slight tilt (about a 1/4") to the outside so that excess water drips from the back. This dripping is normal.


Air conditioners are designed to evaporate some of this water. There is a slinger ring on the fan blade that throws the collected water against the outdoor condenser coil.


  • This design improves the operational efficiency of the air conditioner, so you do not want to drain the water or add a drain hole.
  • Many models do not have a drain plug. For models with a drain plug or subbase water plug, the drain plug is mostly intended to drain the appliance for service or if you are uninstalling the air conditioner for storage. However, the drain plug or subbase water plug may be removed during operation to minimize water in the back of the unit; however, removing it will lower the efficiency of your air conditioner.
It is not normal for water to be dripping inside the room. If this is happening, please take a look at our Air Conditioner - Water Dripping Inside Room article.