What states require air gaps?

Author: Jude Carroll Jr.  |  Last update: Wednesday, May 7, 2025

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

Are air gaps required?

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 you always need an air gap?

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.

Is there an alternative to 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.

What are the two requirements for the air gap?

How Measured: Air gaps shall be measured vertically from the lowest opening of the water supply outlet to either (1) the flood level rim of the fixture or receptor served, or (2) the maximum elevation of the source of contamination.

Dishwasher Air Gap - Is One Required? | From a Plumbing Inspector

What 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.

Do you need a high loop if you have an air gap?

Some municipalities require air gaps, but most find high loops to be acceptable by themselves. The air gap stops any negative pressure from causing back siphoning into the dishwasher by introducing air into the system.

Do I need an air gap if I have a garbage disposal?

They rely solely on basic physics and gravity to do their job. If you have a garbage disposer and a dishwasher, you will definitely want to use an air gap.

Do modern dishwashers need an air gap?

The primary purpose of a dishwasher air gap is to prevent the backflow of dirty water into the dishwasher, which can lead to contamination of clean dishes and potential health hazards. For this reason, air gaps are required to meet plumbing codes in many areas.

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.

What is the main disadvantage with the air gap technique?

Limitations of the air-gap technique include potentially increasing patient dose and geometric blurring (unsharpness) 3.

Is an air gap required in California?

California's building and plumbing codes have specific guidelines regarding kitchen plumbing to ensure safety and sanitation. One such requirement is the air gap, a small but essential fixture in kitchen sinks, particularly when a dishwasher is involved.

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.

What is the air gap policy?

An air gap involves physically isolating a computer or network from other networks to prevent unauthorized access and data breaches. This method creates a literal "air gap" between the secured network and any other unsecured networks.

Can I remove a dishwasher air gap?

Dishwasher Air gap is not required with all modern dishwashers. They have the air gap function internally installed. Older dishwasher drains can be modified to eliminate the air gap on the counter.

Is a dishwasher air gap required in Wisconsin?

It prevents sink drain water from backing up into the dishwasher, possibly contaminating dishes. 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 states require dishwasher air gaps?

Which States Require Dishwasher Air Gaps? In California, Washington, Minnesota and Hawaii, a dishwasher air gap is a mandatory residential plumbing procedure.

Is an air gap necessary?

It creates a separation between the water supply and potentially contaminated water in a sink or other plumbing fixture. 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.

Does a 3 compartment sink need an air gap?

Three compartment sinks should have TWO AIR GAPS.

Can you pour water down an air gap?

Finally, pour hot water down the air gap to deal with any greasy particles. If you can't get any air movement or a clog is still present, you may need to snake it out.

How do I prevent sink water from draining into my dishwasher?

When there is a clog in the line, and it's not draining properly, water pressure in the pipes can increase and force sink water up into the dishwasher drain line. One way to relieve the pressure is to disconnect the sink trap (P trap) underneath the sink and remove the blockage.

Can a dishwasher drain directly into the waste line?

Second, the drain must connect to a proper fitting with a trap that prevents sewer gases from backing into the dishwasher. This trap arrangement already exists at the kitchen sink, but it would need to be duplicated if you made a separate connection directly into the waste line.

What happens if the air gap is too small?

If the air-gap is too small there is a possibility that the rotor will hit the stator and, of course, this is to be avoided. However, the benefits of a small gap are a lower magnetization current for the flux density needed. This improves power factor and reduces electrical power losses.

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.

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