What states require a dishwasher air gap?

Author: Ms. Rae Hauck  |  Last update: Friday, June 19, 2026

If you reside in California, Washington, Minnesota, or Hawaii, installing a dishwasher air gap is mandatory per the plumbing code in these regions.

Is a dishwasher air gap required by code?

Most states even enforce plumbing codes that require dishwasher air gap installation in residential and commercial sinks. If your drain hose is connected to house plumbing lower than 20 inches above subfloor or floor you will need to use an air gap.

Do dishwashers still need air gaps?

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.

Does Texas require an air gap for a dishwasher?

Appliances must have air gaps as required for connections to the sewerage system. Venting must assure a rapid flow of wastewater in the sewage system.

Are dishwasher air gaps required in Nevada?

PLUMBING AND MECHANICAL: 1. The water supply for dishwashers shall be protected by an air gap or integral backflow preventer.

Dishwasher Air Gap-Do You Need One?

Which states require an air gap?

If you reside in California, Washington, Minnesota, or Hawaii, installing a dishwasher air gap is mandatory per the plumbing code in these regions.

What is the alternative to the dishwasher air gap?

However, high loops are popular, inexpensive to install and have proven to be reliable backflow prevention methods. If you opt not to install a dishwasher air gap, a high loop is the best alternative.

Do you need a dishwasher air gap in Wisconsin?

An air gap device is not used in all dishwasher installations and is not provided with the Cove Dishwasher. Air gap requirements vary by state. For example, Wisconsin requires an air gap above or below the sink.

What is the air gap in California?

An air gap between the water supply inlet and the flood level rim of the plumbing fixture, equipment, or nonfood equipment shall be at least twice the diameter of the water supply inlet and may not be less than one inch.

Do Whirlpool dishwashers require an air gap?

It is recommended that the drain line be connected to your house plumbing using a drain air-gap (Part No. 300096) available through your Whirlpool dealer. NOTE: Some other brands of drain air-gaps restrict water flow excessively and can result in incomplete drain.

Does the Bosch 800 dishwasher require an air gap?

Yes you want the drain hose to run up above the base of the sink before it is connected to the outgoing plumbing. This is in the case the water is backing up, it would have to back up visibly in the sink before it could run back to the dishwasher. This is in efforts to prevent leaks.

Does a Thermador dishwasher need an air gap?

If local ordinance requires an air gap, the dishwasher will need to be installed with one. But otherwise, an air gap is not required.

Do commercial dishwashers need a backflow preventer?

A backflow preventer is required to be installed at most commercial properties. It prevents the contamination of the potable water supply.

Can you use a high loop for a dishwasher in California?

It's required by code in California but some people bypass this requirement and have something called a “High Loop” under their sink. A High Loop's operates simply when the dishwasher drain line is attached to the underside of the countertop or sink.

Does a dishwasher need an air gap and high loop?

Both the high loop and air gap methods serve the same purpose of preventing wastewater backflow and are commonly required by building codes to ensure the safe operation of dishwashers. The specific requirements may vary depending on your location and local plumbing codes.

Where is an air gap required?

The use of an air gap is required by plumbing codes for certain plumbing fixtures, such as dishwashers, to prevent the backflow of potentially contaminated water into the clean water supply. If contaminated water backflows, it can cause serious health risks.

What is air gap violation?

An air gap is a security measure that involves isolating a computer or network and preventing it from establishing an external connection. An air-gapped computer is physically segregated and incapable of connecting wirelessly or physically with other computers or network devices.

Is an air gap required for a dishwasher in California?

We're looking to permit our kitchen, and the air gap is the big hangup...we're looking primarily at dishwashers that don't need them, but in California they're required by code nonetheless.

Do commercial dishwashers need an air gap?

Not all commercial dishwashers are fitted with a Class 'A' Air Gap as standard. However, as we previously mentioned, an Air Gap is a legal requirement for dishwashers within commercial kitchens and we, therefore, recommend checking the dishwasher's specification before purchasing.

Is an air gap required in Wisconsin?

According to Wisconsin code, dishwasher drains must have either an air gap or be plumbed to the stack. The 'high loop' method is out of code.

What if my sink doesn't have an air gap hole?

If your sink lacks an available hole for installing an air gap, a plumber can usually drill an opening where needed.

Does a Samsung dishwasher need an air gap?

Ensure the dishwasher's drain hose connected to the sink is not compressed, twisted, or damaged. In some regions, adherence to local regulations requires an air gap or a high loop in the hose to prevent backflow and guarantee efficient drainage.

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