Troubleshooting a Whirlpool Dishwasher With the Water Draining From the Vent Cap

Unscrew the decorative metal cap on the air gap and clean the cap, as well as the plastic air gap outcropping. Remove debris, lime scale or other mineral deposits that may cause the venting function to fail and water to backup, exiting the vent cap.

Check the drain hoses under the sink making sure they have not become kinked or bent. Often when items are stored under the sink they can build up, crowding and dislodging the flexible plumbing hoses from their natural positions.

Do not use too much detergent in the dishwasher or any product except those liquids and powders expressly designed and labeled for dishwashers. Dish soap and laundry soap may look the same, but foam and create heavy suds that can damage or disable your dishwasher. The foam and some water hen build up in the pipes and escape out the air gap, making it seem as though you have a leak.

Ensure that there are no obstructions in the drain piping below the sink. If these pipes are backed up, water flows to the nearest place of least resistance, and that may be the air gap vents. Open up the pipes with a pipe wrench and clean them out or use a snake probing and cleaning them.

Confirm that the dishwasher drain hose connects to the waste pipe, which is t-shaped connection, or into the garbage disposal at a height of at least 20 inches up from the floor. Water cannot overcome gravity if the connections are made any lower and backups will occur.