What Is a Dishwasher Air Gap? How It Works & Why It Matters

How Does a Dishwasher Air Gap Work?

A dishwasher air gap creates a physical break between the dishwasher’s drain hose and the sink drain or garbage disposal. This gap prevents dirty water from flowing backward into the dishwasher if a clog or backup occurs.

Why Are Air Gaps Important?

Dishwasher air gaps can protect your kitchen and your health, preventing dirty water, bacteria, and food waste from re-entering the dishwasher and coming into contact with clean dishes.

They also prevent messy and costly problems like water backing up onto your countertop, under the sink, or into cabinetry.

Do You Need a Dishwasher Air Gap?

Whether you need a dishwasher air gap depends on local plumbing rules and how your dishwasher is installed. In many U.S. cities and counties, including those that follow the Uniform Plumbing Code (UPC) standards, air gaps are required by local plumbing codes.

Do All Dishwashers Come with Air Gaps?

No, most dishwashers do not include an air gap. The air gap is usually included separately during dishwasher installation or added later if needed.

How to Install a Dishwasher Air Gap, Step by Step

• Turn off the dishwasher and disconnect the power for safety.
• Find the pre-drilled hole near your sink (or remove the sink hole cover).
• Insert the air gap fitting into the hole, then secure it from below with the provided nut.
• Connect the dishwasher drain hose to the smaller inlet on the air gap.
• Attach a second hose from the larger outlet on the air gap to the sink drain or garbage disposal.
• Tighten all hose clamps to prevent leaks.
• Restore power and run a short cycle to check for proper drainage and leaks.

If your sink or countertop doesn’t already have a hole, you may need a professional installer to avoid damaging stone, quartz, or stainless-steel surfaces.

Maintenance & Troubleshooting Tips

Like any kitchen plumbing component, a dishwasher air gap may occasionally need attention. Regular checks can help you catch minor problems before they turn into bigger issues.

What If Water Comes Out of the Air Gap?

Water coming out of the air gap usually means there’s a blockage in the drain line or garbage disposal. Here’s how to fix it:

• Stop the dishwasher and check for clogs before running another cycle
• Once the blockage is cleared, the air gap should drain normally again

How to Clear a Clog in the Air Gap

Clearing a clog is usually straightforward, and can restore proper drainage quickly. Here’s how to handle it:

• Remove the air gap cap from the top
• Check for food debris or buildup inside
• Clear the blockage with a small brush or pipe cleaner
• Rinse with warm water before replacing the cap

Cleaning Tips AudioVolumeMute

Routine cleaning and maintenance can prevent future clogs and overflow issues. Follow these tips to keep your air gap clear:

• Remove and rinse the air gap cap periodically
• Clean the inside with warm water and mild soap
• Check connected hoses for buildup or kinks

When to Call a Professional for Air Gap Installation

While you can usually install a dishwasher air gap on your own, some situations call for professional help. Hiring a pro can help you avoid leaks and drainage problems down the line.

You may need a professional if…

• You’re unsure where or how to install the air gap
• Your sink or countertop doesn’t have an existing hole
• Water continues backing up after clearing clogs
• The dishwasher isn’t draining properly

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