What is a Dishwasher Air Gap?

Portable Dishwashers

The dishwasher air gap options are numerous, with different styles, finishes and some come either with or without covers. Dishwashers are among the types of appliances that either need or do not need an air gap as part of the installation.

Many people don’t care much how their sink works. As long as it is able to bring out water, then they are satisfied. The same can be said with dishwashers, although some owners are now getting concerned whether or not their dishwasher air gap is really working. The way sinks are made these days are done in a very convenient way that it will make dish washing routine faster.

KOHLER K-9110-VS Air Gap Body with Cover is one that we really think highly of, available in many different finishes including Oil-Rubbed Bronze, Vibrant Brushed Nickel & Polished Chrome. Which of these Kohler products do you like the best ?

Dishwasher air gap, or simply air gap, is the vertical space in between the flood level and the water outlet of a particular fixture. The simplest image for this is the space in between the sink rim and the wall mounted faucet. The space between them is the air gap. Water is able to flow easily into the sink from the faucet, but there is no way for the water to flow into the sink from the faucet when you don’t modify the system itself. If you take care of such arrangements beforehand, this will prevent the contaminants getting into the sink that comes from the potable water supply which is done by siphonage. This is also the least expensive way of backflow prevention.


The dishwasher air gap options


Design House 522953 Dishwasher Air Gap, Satin Nickel Finish is another popular option, coming in at a great price point for consumers not wanting to spend more than required. We like this Design House model as it offers value for money.


For those with a slightly bigger budget and Moen kitchen fittings, consider the Moen 105895ORB Air Gap with Matching Escutcheon, Oil Rubbed Bronze.

This Moen oil rubbed bronze matches Moen Mediterranean Bronze color range of products.



The air gap is a common term referring to home plumbing, particularly the dishwasher air gap. The air gap, in this case, is seen visibly above the kitchen’s countertop. It comes in a small cylindrical fixture that is mounted in a parallel way together with the faucet. Right below the countertop, the dishwasher’s drain pipe feeds the “top” of this air gap, while the bottom is connected to the sink drain right below the sink’s basket, or sometimes directly into the garbage disposal unit. The air gap can work perfectly and is convenient for any households, given that they are well maintained and properly installed. It will also prevent the drain water from getting back up right into the dishwasher, which can possibly contaminate the dishes. Water that is flowing from a fixture that goes out into the sink means that there is a need for it to be repaired or just maintained.

dishwasher air gap options

dishwasher air gap options

To give you a clearer understanding regarding the air gap, imagine if you were to take out the air gap and then attach a hose directly to the faucet. You lower the hose into the sink that is filled with contaminated water. Under such conditions, the contaminated water in the sink will get siphoned into the pipes through the faucet and the hose. The contaminated water will then get dispersed through the whole drinking water system.


How does the Dishwasher Air Gap work?

Installing the air gap in the kitchen sink solely prevents the contamination of water where the dishwasher is located, it also protects the water supply of your neighborhood. You might think that you got everything solo under you, and when something happens to your water, you are only affected by it. If you have imagined the aforementioned scenario, you can already imagine the negative effect it can cause to the public water supply. In the event that there is a complete halt to the water pressure, the sewage that goes into overflow in the dishwasher could get transported into the water supply.


Plumbers are usually the ones responsible for installing the air gap in the sink. They utilize the pre-drilled hole right next to the faucet. If the holes provided are already in use by a soap dispenser or sprayer, the plumber will drill a new hole right next to it to install the dishwasher air gap. While the other options will free the already drilled holes, they are not recommended because they are less reliable, according to many experts. You can always look to fit the undercounter dishwasher air gap yourself, if you feel confident enough.


The check valves are considered one of the other antisiphon device types that are oftentimes utilized with the dishwashers. But when a small food particle gets stuck into the valve, it can often be the cause of its failure. Most authorities in the plumbing community consider such things as less reliable compared to the air gap. There is the third option, which is referred to as the high loop installation. This is entirely dependent on the force of gravity that exceeds the force present in the sewer backup. While these kinds of installations usually do not cause such problems, they are not completely fail-safe.


Most Common Installation Defect of Air Gap

If the drain hose is not properly installed, it will affect the flow of water into the sink, especially into the dishwasher. In fact, this is the most common mistake when the dishwasher air gap is installed. But experts say it is the easiest problem to solve that even with ample plumbing experience of a homeowner can do it themselves.


Sometimes in this setup, the drain is connected directly to the trap’s sewer side. The water always sits in the bottom of the trap, thus preventing the sewer gasses from getting into the house. The drain of the dishwasher must always be connected before the P-trap is done. It must never be the other way around, which is also one of the many causes for this major trouble. With an improper installation like this, the sewer gasses can possess a great potential in going back to the dishwasher system.


Do You Need the Dishwasher Air Gap?

Many homeowners are asking this as to whether or not it is really necessary to have the air gap. As you have already read from above, the purpose of the air gap is to prevent grime, dirt, and sediment from getting into the dishwasher while it is cleaning your dishes.


Another reason why you need to have the air gap installed is because of the noise. Experts say that the air gap will aid in muffling some of the noise that is made by the dishwasher while it is washing the dishes.


The most important of all would be health concerns. As the air gap prevents the contaminated water from infiltrating the dishwasher system, it will also prevent the people that use the dishes inside from possibly becoming ill.


Dishwasher air gap cover

You may already have the dishwasher air gap under sink  but not got a dishwasher air gap cover to go with your purchase. Not all air gaps come complete with a dishwasher air gap cover

The Delta Faucet 72020-SS Accessory Air Gap, Stainless is one we think looks quite funky. This Delta item is available at a very reasonable buying price.


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