Everything You Need To Know About Dishwasher High Loop

Photo of author
Last updated:

In today’s world, the dishwasher has become an indispensable appliance in modern kitchens, offering convenience and efficiency in cleaning dishes.

However, to ensure the optimal performance of a dishwasher and prevent potential issues, it is crucial to understand and implement certain design features, such as the dishwasher’s high loop.

In this comprehensive article, we’ll explore the concept of the dishwasher high loop, the reasons for its importance, and how it differs from an air gap.

So let’s begin, shall we…?

What is a high loop on a dishwasher?

A dishwasher high loop is a plumbing component made to stop the backflow of unclean water from the kitchen sink into the dishwasher. It entails raising the dishwasher drain pipe above the level of the sink and adding a loop to it. This arrangement serves as a barrier, keeping wastewater out of the dishwasher.

Still confused? See the image below of how a dishwasher drain appears…

Visuals of a high loop on a dishwater
Diagram of a dishwasher high loop

Purpose of a High Loop

Between washing cycles, if you see any standing water at the bottom of your dishwasher, likely, that the drain line is not elevated enough. Therefore, from a plumber’s point of view, it has two basic purposes:

  1. The first and most crucial thing is ensuring efficient wastewater drainage by rising hydrostatic pressure during the drain cycle and preventing siphoning. 
  2. The second purpose is to avoid polluted water backing up from the sink drain or garbage disposal into the dishwasher.

4 Reasons Why You Need a High Loop

Now that you know what the dishwasher high loop is used for, you must be thinking if it’s right for you. Well, the high loop is necessary for four reasons:

1. Maintaining Hygiene

Installing a dishwasher high loop is mostly done for hygienic reasons. Without it, contaminated water from the sink could recirculate into the dishwasher, possibly bringing with it food scraps, grease, and dangerous bacteria.

2. Compliance with Building Codes

We all know that many places have building codes and plumbing regulations that mandate the installation of a dishwasher high loop. Potential health risks are to be avoided, and the plumbing system is to be kept in good shape, under these standards. For your kitchen to pass inspection and adhere to the necessary standards, compliance is crucial.

3. Preserving Dishwasher Components

The pump, motor, and spray arms may all be damaged if polluted water backflows into the dishwasher. This damage has the potential to lower the dishwasher’s lifespan, raise maintenance expenses, and degrade performance over time. Such damages are avoided by the high loop, saving you money on maintenance and replacements.

4. Peace of Mind

By having a dishwasher high loop in your kitchen, you can rest assured that the dishwasher is functioning optimally and is less likely to encounter drainage issues. This peace of mind extends to the cleanliness of the dishes, ensuring they are safe for consumption.

RELATED: Estimated Plumbing Installation Cost Online Calculator

Dishwasher High Loop Installation

A high loop is typically quite simple to install. There are different ways to accomplish this, but using a screw and a zip tie is the simplest. For a skilled plumber, should take no more than four to five minutes to complete.

Here’s great video simplifying the installation process of a high loop dishwasher drain:

Installation of a dishwasher high drain loop by ASPEC Residential Services, LLC

And please keep the following details in mind when connecting your dishwasher drain pipe to your plumbing:

For optimal effectiveness, mount the high loop as close as possible to the underside of the cabinet. And the P-trap on your sink’s plumbing should be located upstream of the connector.

Never connect your dishwasher drain pipe at the P-trap or downstream of it, as this can result in backflow and release of sewage gases from the drain pipes. In addition to this, it is best to avoid connecting your dishwasher drain pipe to garbage disposals.

High Drain Loop Bracket

The high drain loop bracket is a handy accessory that holds the drain hose in an inverted U position to prevent water backflow. It will function with the majority of dishwashers that employ a 1/2″ or 5/8″ drain pipe. The interior diameter of the hose serves as the basis for measurement.

Even more easily installed high loop brackets are available on Amazon and Plumbing Supply Stores. No tools are required. Plus, it can install quickly with the supplied 3M VHB tape, the predrilled holes and screws!

High Drain Loop Bracket available on Amazon
High Drain Loop Bracket sold on Amazon

Dishwasher High Loop Vs Air Gap

While both dishwasher high loops and air gaps serve the purpose of preventing backflow and contamination, they differ in their mechanisms and installation.

As mentioned earlier, a dishwasher high loop involves installing a loop in the dishwasher drain hose and positioning it higher than the sink’s bottom. This elevation acts as a barrier to prevent water from flowing back into the dishwasher.

An air gap is a physical gap or space between the dishwasher’s drain line and the sink’s drainpipe. It is often installed on the countertop near the sink. When the dishwasher drains, the wastewater passes through the air gap before entering the drainpipe.

Air Gap figure
Diagram of an air gap

The air gap provides a physical break in the plumbing system. It ensures that even if the sink’s drain is clogged, wastewater cannot flow back into the dishwasher.

Pros and Cons of Dishwasher High Loop and Air Gap

Simple installation and is cost-effectiveNot appropriate for many plumbing setups, especially in older homes
Reduces the risk of clogs in the air gapIn some places, local building regulations might not be met
Takes up less space compared to an air gapDoes not provide a clear indication of a blockage or obstruction
Has an aesthetic appeal as it remains hidden behind the dishwasher
Pros and Cons of Dishwasher High Loop
Provides a visible indication of a clog or blockageRequires additional space on the countertop for installation
Offers an additional layer of protection against backflowMore expensive and complex to install compared to a dishwasher high loop
Complies with plumbing codes in most regionsHas potential for debris accumulation and clogging in the air gap
Pros and Cons of an Air Gap

Choosing The Right Option

When deciding between a dishwasher high loop and an air gap, several factors come into play:

1. Local Building Codes

Check the plumbing regulations in your area to determine whether a dishwasher high loop is sufficient or if an air gap is required for compliance.

2. Plumbing Configuration

Consider the layout of your plumbing system and the available space. A high loop might be the more practical choice to deal with the limited space on the countertop.

3. Personal Preference

If you prefer a cleaner look with fewer visible components, the dishwasher high loop might be the better option.

Frequently Asked Questions

Which dishwasher component detects water overflow?

When there is enough water in the dishwasher, the float switch signals the control board. Your dishwasher may overflow with water or fill up when it shouldn’t if it isn’t functioning properly.

Why won’t my dishwasher drain properly?

Water may not drain out of the dishwasher properly if the hose has come free and is no longer coiled up higher than the appliance’s level. You can either build an appropriate air gap or put the hose back in its proper high-loop position to fix the issue.

How durable are expensive dishwashers?

Many expensive dishwashers in the market nowadays will last longer than usual, especially if you take care of them. For instance, Bosch Dishwashers normally last for 10-12 years, whereas there are other companies that claim that their dishwashers last a remarkable 18-20 years.

How much does installing a high loop cost?

The cost of installing a high loop is not much. It just takes a few minutes of your time and some bucks for the screw and a clip or zip tie.

Are dishwashers more affordable than hand washing?

When compared to hand washing, we believe that using the dishwasher will be more cost-effective, especially if you wash by hand while the water is still running.

Our Final Thoughts

So one thing that we all agree on now is that the dishwasher high loop is an essential plumbing component that guards against contamination and backflow. It guarantees the dishwasher runs well, increases its longevity, and maintains the cleanliness and safety of our dishes.

As far as Dishwasher high loops and air gaps are concerned, they have got the same function, but operate differently and require different installation procedures.

The decision between the two ultimately comes down to regional building regulations, plumbing design, and personal preferences.

Keeping everything aside, we strongly believe adding a backflow prevention function to your dishwasher setup is a smart move that will enhance your kitchen and your peace of mind for sure.

Leave a Comment