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What is a dishwasher air gap?

A dishwasher air gap is a cylinder fitting that connects the kitchen sink drain to your dishwasher, preventing dirty water from flowing into the dishwasher as well as out of it during a wash cycle. Whirlpool® Dishwashers have several important features that help keep dishes clean, including the small yet effective dishwasher air gap.

Because your dishwasher drains directly into your kitchen plumbing, the dishwasher air gap stops any dirty dishwater from re-entering the appliance. Read on to learn more about dishwasher air gaps and how they work.

How does a dishwasher air gap work?

Dishwasher air gaps work by separating two branches of hose with an unpressurized gap of air to help prevent cross-contamination between the dishwasher and drain. While one branch of the air gap fitting connects to the appliance, the other connects and descends to the garbage disposal. Dirty dish water is pumped out of the appliance and into the air gap through the hose, where it is then released to the drainage site through the second branch of tubing.

Is an air gap necessary for a dishwasher?

Air gaps function on the principle of basic physics. Because it’s impossible for water to flow back through an unpressurized gap of air, the air gap can prevent water from being siphoned out while the dishwasher is in use, and helps keep dirty, used water from re-entering the unit. While there are some alternatives to keeping your dishwasher water flowing in the right direction, like using a high loop or standpipe, air gaps can help prevent siphoning or backflow and have been mandated by building codes in several states.

Air gaps can also help prevent sink water from being forced into the dishwasher in the event that the drain or garbage disposer becomes clogged. Most dishwashers also incorporate check valves in the drain system to prevent this from happening. For additional protection, the drain hose can be routed to the underside of the counter to negate gravity from allowing sink water into the unit should the check valve fail.

Do new dishwashers need an air gap?

A dishwasher air gap’s purpose is to help ensure that the water being used in your appliance is fresh and isn’t siphoned out early during a wash cycle. If you live in a state where air gaps are mandated by law, even a new dishwasher will require one to be installed. A drain hose that is connected to house plumbing lower than 20 inches above the floor will need an air gap. Check your local codes and requirements.

Unless mandated, dishwasher air gaps are not always recommended by professionals. Dirty water can also be prevented from entering your dishwasher by routing the drain hose beneath the counter at the same height as a full sink of water. This method, known as the high loop method, uses negative pressure to help prevent dirty water from entering your dishwasher. Some Whirlpool® dishwashers are designed with built-in air gaps on the drain end. However, these devices are not recognized by code agencies and will not replace the use of a through-counter device where required by code.

How do you install an air gap for a dishwasher?

To install a dishwasher air gap, start by locating the air gap hole in your countertop. The hole may be concealed by a flat covering. If no covering is present, you may need to drill a hole to house the air gap. Refer to the manufacturer’s instructions for your specific air gap or any instructions within your owner’s manual for the size of the hole needed and for further installation guidelines.

Should water come out of the dishwasher air gap?

If your dishwasher air gap is leaking water, this indicates a problem that will need to be corrected. Water spilling from an air gap is typically caused by a clog that can oftentimes be cleared out by trying a few simple methods on your own.

How do you clear a dishwasher air gap?

To clear a clog from your dishwasher air gap, remove the cover and use a long-handled bottle brush to remove food particles that may be stuck in the tubing. You can also try clearing the clog by placing a paper towel tube over the opening and blowing into it to help dislodge the debris. 

If neither of these methods work and your garbage disposal was recently installed, it’s possible that the knockout plug was never removed. To remove the knockout plug, unplug the disposal and disconnect the hose that links it to the air gap drain. Use a hammer and screwdriver to tap the knockout plug out of place to allow water to flow through the tubing. Once you have reconnected the drain hose, reach inside the disposal to remove the loose plug before plugging the disposal back into the power supply.

If none of these techniques work and the air gap is still leaking, it may be time to contact a professional. Repair and replace services from Whirlpool brand provide professional help when you need it.

How do you clean a dishwasher air gap?

A dishwasher air gap is intended to only permit air through the drainage system, so it may not be necessary to clean it consistently. However, if you notice buildup in the air gap, clean any buildup that may have accumulated by removing the air gap cover and rinsing out the cap, ensuring the air gap isn’t clogged. Check to make sure the air gap is tightly secured.

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Shop Whirlpool® Dishwashers

Spend more time enjoying meals with your loved ones and less time worrying about clean-up with Whirlpool® Dishwashers. Features on select models, like an additional 3rd Rack and an Adjustable 2nd Rack, provide enough room for all the essentials when it’s time to clean up. If you’re ready to purchase a Whirlpool® Dishwasher, you can choose from several flexible and long-lasting options.

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