Do You Need an Air Gap for Dishwasher? (Important Info Inside)

Do you need an air gap installed for your dishwasher to prevent cross-contamination from the rest of the drains in your home? That is a good question and needs to be investigated if you want to add a dishwasher to the kitchen appliances in your home.

We will take a look at what an air gap is and how it will be beneficial for your dishwasher at home. We will also take a look at how to use an air gap to make your dishwasher a much safer appliance to use.

Read on and find out what an air gap is used for and how it will improve your home environment when used with a dishwasher.

What Is an Air Gap?

An air gap is a small device or gadget which is mounted above the countertop in your kitchen to prevent contamination of your dishwasher. It will prevent dirty water from flowing back into the dishwasher and keep it much more hygienic for your safety.

This reverse flow can easily happen if there are blocked drains in your home and the water flows back into the dishwasher instead of down the drain. The dishwasher air gap works the same way as an anti-return flow device to prevent the dirty water from running back into the dishwasher.

It will also ensure that only a clean water supply is flowing into the dishwasher to prevent any bacteria from building up inside it.

Do You Need an Air Gap For Your Dishwasher?

It is safe to install an air gap with the initial dishwasher installation so you will have a clean water supply from the word go. If you do that, you do not need to worry about contaminated water when using your dishwasher to clean the dishes.

You may never know when the sink drain may become blocked unexpectedly and not drain the water as it should. In many cases, the plumbing codes of most areas require that an air gap be installed between the home drain and a dishwasher.

The most simple air gap that is often installed for dishwashers consists of a loop method to prevent the backflow of the water. Others use a simple vertical pipe installed in the drain hose that prevents the water from going back and only forward or down.

Standard air gaps are mostly made with a double leg inflow and outflow to prevent any backflow from the drainpipe. It is better to connect the hose of the air gap to the garbage disposal for a clean and proper working system.

How Does a Dishwasher Air Gap Work?

An air gap simply separates the hose from the dishwasher from the hose that leads to the garbage disposal or drains. When the dishwasher pumps water out, it is pumped to the air gap and is removed by the drain hose to the drain.

This system removes the food particles from the water so that it does not interfere with the normal flow of the water. This action means the filthy water from a blocked drain can not flow back into the dishwasher to contaminate it with old food and bacteria. 

Water will not overflow from the air gap into the dishwasher hose, keeping it safe from any backflow of filthy water. So no dirty drain water will ever get back to your dishwasher and thus you are left with a safe option to wash your dishes.

Dishwasher Air Gap Maintenance

To keep the dishwasher safe, you still need to keep the air gap clean on a regular basis to prevent bacteria build-up. Anyone can do this cleaning in a few simple steps. Just follow these instructions to clean a standard air gap on your dishwasher.

  1. Remove the chrome cover located at the top of the air gap
  2. Next, you should unscrew the plastic cap of the air gap
  3. Remove all materials and dirt that accumulated inside the air gap
  4. Clean it out by rinsing it with clean water
  5. Make sure the air gap fitting is clean from any material
  6. Check the hose of the air gap from the dishwasher to the drain or garbage disposal to make sure it is not blocked
  7. It is good practice to check for any leaks after you have cleaned it to keep it in an excellent working condition
  8. Make sure that you have removed all materials inside the air gap to prevent unpleasant odors in the future

Do You Need an Air Gap for Dishwasher

Importance Of an Air Gap

If you experience any water flooding while you use your dishwasher, it is time to install an air gap for the dishwasher. It is also required by most plumbing codes to have an air gap installed in your house when you install a new dishwasher.

What Is a Dishwasher Air Gap Alternative?

If it appears that your air gap does not work as it should, there are always other ways to keep your dishwasher safe. You can use a high loop in the hose of your dishwasher to prevent the drain water from flowing back into the dishwasher.

It will create a closed-loop system in the water between the dishwasher and the drain and is very easy to install. This high loop can be installed inside the kitchen sink cabinet to keep it out of the way and out of the eye.

When installed just below the kitchen sink, it will easily keep the filthy drain water away from your dishwasher.

Does a Dishwasher Come With an Air Gap?

Some dishwashers out there are made with an air gap attached to the dishwasher drain hose to make it easier. In most cases, the air gap is located at the top of the sink of your house and is covered with a small chrome cap.

But it is not really part of the dishwasher, so you need to attach the air gap to the dishwasher hose yourself. You can also ask the technician who initially installed the dishwasher to install an air gap in your home.

Dishwasher Air Gap Installation

If you like to do things for yourself, you can always install an air gap in your kitchen sink if you are one of those people. It is a simple job and can be done without the help of a technician. Just follow the steps indicated here:

  1. First, you will need to find the air gap hole located in the kitchen sink. The hole might be covered with a plastic disk.
  2. Remove the disk to expose the hole of the air gap where you need to install it.
  3. If there is no air gap hole in the sink, you need to drill a 1 ⅜-inch hole in the countertop.
  4. Make sure you drill the hole very close to the rim of the kitchen sink.
  5. In the case of a marble countertop, you will need the help of a professional to drill the hole.
  6. Connect the air gap connection with the actual fitting on the dishwasher hose.
  7. The gap connector can be installed by connecting an ⅝ inch pipe to the same size leg of the air gap.
  8. Use a stainless steel clamp to secure the pipe to the leg of the air gap.
  9. Secure the other leg of the air gap to the house of the garbage disposal unit or to the drainpipe of the kitchen sink.
  10. If you connect it directly to the drain, protect the hose with a hose clamp.
  11. A dishwasher air gap fitting is the same standard size no matter what brand you buy.
  12. When you are done connecting the hoses, you can now push the air gap through the air gap hole from below.
  13. Anybody can do this by removing the cover from the air gap, so it will easily fit through the hole.
  14. You can thread the nut of the air gap so you can tighten it against the counter.
  15. Ask someone to hold it in position while you tighten it, so it does not spin.
  16. With the use of the right-sized wrench, you can now wholly tighten it to stabilize it.
  17. Replace the cap of the air gap, and you are ready to use it.

To test if your installation works appropriately, use the dishwasher on full cycle and look for leaks with the air gap and tubing.


It’s would be best to have an air gap installed for your dishwasher to keep it safe from contamination from a blocked drain. It is also part of the plumbing code to have an air gap installed to protect your family from illness and keep your home safe.

It is always good to stay within the rules that apply to all types of building codes for your own protection.

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