An air gap is part of the necessary plumbing required when installing a dishwasher. In fact, local plumbing code typically requires a properly installed air gap for every dishwasher. But what is a dishwasher air gap and why is it so important?

What is a dishwasher air gap?

The dishwasher air gap is very important because it prevents sewage from flowing back into the dishwasher. If your sewage line backs up, the water will drain up through the air gap into your sink rather than back into your dishwasher.

Plumbing code typically requires an air gap be installed with a dishwasher to ensure any sewage back-up does not contaminate your dishwasher. Air gaps are the most effective anti-backflow devices, and therefore should not be substituted with another method.

Where is the dishwasher air gap located?

The air gap is typically located in parallel with the sink faucet. Usually, it will be covered by a chrome cylinder. It’s important that the chrome cylinder is installed and the 3 slats are pointing toward the sink (so the water flows into your sink, not behind it!).

What is a dishwasher air gap

Can I Use a Different Anti-backflow Devices?

Check valves are sometimes used as an alternative to an air gap, but experts consider them to be less efficient since they tend to malfunction if food gets stuck in the valve.

As an alternative, handymen may recommend installing the drain hose using the high loop method. Although this method will prevent sewage from siphoning into your dishwasher under low-pressure back-ups, it will not prevent an overflow if the back-up is high pressure or high sewage. For this reason, this method is not typically recommended.

If you’re installing a new dishwasher or received a warning from an inspector that an air gap is required on your current dishwasher, your best bet is to contact a plumber or appliance technician to install the air gap.

What kind of problems can a dishwasher air gap experience?

In some instances, water can flow out of the dishwasher air gap. A damaged seal or a blockage in the pipe can be responsible for this. Other potential problems include a clogged air gap and a clogged vent. If you think that your air gap is clogged, check out this video that shows you how to clean your dishwasher air gap.