How to Troubleshoot a Dishwasher Air Gap

An air gap's job is to prevent back flow.

Sometimes, a dishwasher won’t drain because the air gap is fouled up. The air gap is the cylindrical metal cap that you often see on a sink next to the faucet. The air gap is mandated by many municipal plumbing codes. Its job is to prevent back flow -- also called siphonage -- of undrinkable dishwasher water into the potable, fresh water supply. Invariably the problem is that it gets plugged, preventing the correct drainage of the dishwasher.

Things You'll Need

• Toothpicks
• Chopsticks

Instructions

1. Pull the metal cap off the air gap. It isn’t attached with fasteners and you can pull it straight up and off.

2. Inspect the air gap. The air gap is the polypropylene device below the metal air gap cover. Look for dirt or debris such as old tooth picks or hair. Pieces of broken glass can be big enough to block the air gap.

3. Carefully remove any debris with your fingers. Use toothpicks or chopsticks to clean the air gap out. If you have a spray attachment on your faucet, give the whole thing a good power-spraying. They key is to establish air flow again.

4. Replace the cover and try a dishwasher cycle again.

References

• Delta Classic Kitchen Air Gap
• Frigidaire Dishwashers User Guide