Many people realize the dishwasher connects to a little device on top of the sink, some even know that it is called an air gap. However, many people wonder, “What is an air gap for?” The air gap is there to prevent water from being siphoned out of the dishwasher. When water flows through the drain hose, it creates a suction on the water still in the dishwasher. The air gap creates a hole for air to get in, preventing this suction. This ensures that water only leaves the dishwasher when it is supposed to, when it is pumped out.
Another benefit of an air gap is that if the drain hose becomes clogged, the dishwasher can still pump out the water. Instead of flowing through the hose as it should, it can flow out the air gap and into the sink. The reason it is in the plumbing code in some communities is that it ensures sewage can never back up into the sink and then into the dishwasher, contaminating the water supply through the connection to the fresh water supply.
Caution: Please read our safety information before attempting any testing or repairs.
Steps to Clean the Air Gap
The dishwasher’s drain line usually connects to an air gap mounted at the countertop level on the sink. The drain line continues from the air gap to either the garbage disposer or directly to the sink drain. If the drainage hose between the air gap and the drain is partially or completely blocked, water from the dishwasher will flow out of the air gap and into the sink.
Step 1: Safety First
- Turn Off Power: Unplug the dishwasher or shut off the power at the fuse box or breaker panel to avoid electrical shock hazards.
- Turn Off Water Supply: If necessary, turn off the water supply to the dishwasher.
Step 2: Remove and Inspect the Air Gap Cap
- Remove the Cap: Pull off the chrome cover of the air gap by lifting it straight up. Underneath, there may be a plastic cap that unscrews or pops off.
- Inspect for Debris: Check inside the air gap for any visible debris or blockages.
Step 3: Clean the Air Gap
- Use a Brush: Use a small brush (an old toothbrush works well) to clean out any debris or buildup inside the air gap.
- Flush with Water: After brushing out the debris, flush the air gap with water. You can use a turkey baster or a small funnel to pour water through the air gap.
Step 4: Check the Drain Hose
- Disconnect the Hose: The drain hose from the air gap to the garbage disposer or sink drain may be clogged. Disconnect this hose to check for blockages.
- Flush the Hose: Use a garden hose or a strong stream of water to flush out any debris from the drain hose. If the hose is heavily clogged, consider replacing it.
- Inspect the Garbage Disposer: While the hose is off, check the garbage disposer’s dishwasher inlet to make sure it is clear.
Step 5: Reassemble the Air Gap
- Reattach the Hose: Reconnect the drain hose securely.
- Replace the Cap: Put the plastic cap back on and then the chrome cover.
Step 6: Check for a Knockout Plug (If Applicable)
- New Installations: If the garbage disposer was recently replaced or the dishwasher is newly installed, check for the garbage disposer knockout plug. The dishwasher drain line connects to the garbage disposer, and at that connection is a plug that must be removed before using the dishwasher. If left in place, the water cannot drain properly and will spill out from the air gap.
Step 7: Test the Dishwasher
- Restore Power and Water Supply: Turn the power and water supply back on.
- Run a Test Cycle: Run a short test cycle to ensure the dishwasher drains properly and the air gap is functioning correctly.
Step 8: Address Persistent Problems
- Slow Drains: If the problem persists, it may be due to a slow drain. Clear the drain with a mechanical device, as chemicals are not very effective for slow drains because they flow through too quickly. See our plumbing section for more information.
By following these steps, you can effectively clean the air gap and ensure your dishwasher operates correctly. Regular maintenance of the air gap will help prevent blockages and maintain the efficiency of your dishwasher.
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