Do You Need An Air Gap For A Garbage Disposal?

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Some people think that the air gap helps the garbage disposal run well. While others believe it’s an unnecessary expense. So which team do you belong to? Do you need an air gap for a garbage disposal?

We will explore the purpose of an air gap. Then, you can tell if your dishwasher system requires one. Let’s get started!

What Is A Dishwasher Air Gap?

Air gaps are fixtures attached to the counter or the sink. They separate two hoses in the dishwashing system:

  • One hose directs wastewater from the dishwasher.
  • The other hose transmits water to the drain.

Those hoses don’t intersect thanks to the separation, preventing dirty water from contaminating the dishwasher.

Here is how the air gap works:

  • The wastewater exits the dishwasher and travels into the hose running to the air gap.
  • The water runs into the second hose, where it goes down to the garbage disposal.

Two branches of the air gap always rest beneath the countertop. The heading is visible above your counter’s surface near the faucet.

Meanwhile, the air gap is the one beneath the heading. If the drain or tubing gets clogged, the holes in the fixture will let the water run into thought.

So if you see the water from the air gap traveling to the sink, there can be a blockage in the drain pipe or tubing.

The air gap is located near the faucet
The air gap is located near the faucet

Do You Need An Air Gap For A Garbage Disposal?

Yes. The air gap is a good way to avoid cross-contamination in the water in your dishwasher. Moreover, plumbing codes may ask you to install the air gap for your garbage disposal.

Reduced risk of cross-contaminating

Although there are many methods to prevent contamination in the dishwasher, air gaps are the best. They don’t feature any moving parts, as gravity is the key to their operation.

Without the air gap connecting the discharge of your dishwasher to the garbage disposal, the wastewater may travel back to the dishwasher instead of flowing to the disposal as expected.

As you can guess, bacteria will contaminate the dishwasher. Think about your health when dining with dirty dishes, then.

Plumbing codes

Plumbing codes require dishwasher air gaps in many places. For example, in Washington, Hawaii, California, and Minnesota, air gap installation is a mandatory plumbing procedure in households.

Besides, other regions in the country consider air gaps necessary. When assembling a dishwasher, plumbers must set up the air gap connection. Without this installation, your house won’t get the code, making it difficult to sell in the future.

Installing the air gap is necessary for many reasons
Installing the air gap is necessary for many reasons

How To Install An Air Gap For A Garbage Disposal?

You can install an air gap for your garbage disposal and dishwasher by following these steps:

Step 1: Find the air gap hole

Many counters already have a hole. If not, a flat cover may be concealing it. Then, you need to remove the cover.

If your counter doesn’t have an air gap hole, drill one. It should be near the sink’s rim so your air gap has enough room to drain once the pipes overflow.

Before drilling, remember to tape around the section with the hole to protect the counter. If you have a marble or granite countertop, the drilling will be much more difficult. Then, you’d better ask for professional help.

Step 2: Attach the air gap to the drain hose of the dishwasher

The drain hose of your dishwasher links to the smaller leg of the air gap. You need to securely tighten the tube to the air gap using hose clamps.

Step 3: Connect the air gap to the garbage disposal

Measure, then cut a tube to attach the air gap to the garbage disposal or the drain. A hose clamp can help you secure it properly.

There are two options at this step:

  • Garbage disposal: If you connect the air gap to your garbage disposal, find the tube in the disposal unit. If the air gap doesn’t have this disposal, find the metal plug in the tube and remove it.
  • Drain: Another option is to connect the air gap to the drain. In this case, attach the tube to the tailpiece that links the sink to its drain. Then, secure it with a hose clamp.

Step 4: Secure the air gap

Take off the vanity cover of the air gap heading. Then, pull it through the hole on your counter from underneath.

Threat the nut on the threads of the air gap to tighten it against your counter. You may need somebody to hold it in position so it won’t spin while you are securing it.

After threading the nut by hand and stabilizing the air gap, fasten the air gap with a wrench. Next, reattach the vanity cover on the air gap.

Step 5: Test your installation

Run the dishwasher to check for leaks in the tubing connections and your new air gap. Besides, there shouldn’t be any water flowing out from the air gap and garbage disposal.

Five steps to install the air gap
Five steps to install the air gap


The air gap prevents water contamination when running your dishwasher. Moreover, it’s a rule you don’t want to ignore in some regions.

Hopefully, you will find this guide helpful. For any further information about the air gap installation, please feel free to ask. Thank you for reading!