What Is A Dishwasher High Loop?


What is a Dishwasher High Loop?

A missing dishwasher high loop is a common inspection finding especially in older construction or when renovations are completed by someone other than a licensed plumber or certified appliance installation contractor.

So what exactly is a a high loop and why do we need it- A dishwasher High Loop is used to prevent water in the sink or garbage disposal from leaking back into the dishwasher when overfilled or clogged. 

So who cares? The Dishwasher is made to have water in it, right?

Missing Dishwasher High Loop

What Is That Smell?

Yes, the appliance is designed to have water in it when controlled by the dishwasher input. And as designed, when clean dish water is soiled by the dishes it is quickly drained back out.
However, when this trap is missing, water leaks from the sink will back up into the dishwasher and are not drained quickly enough. This creates a rancid smell in the dishwasher even if water sits as little as few hours at a time. 
No High Loop With Waste Disposal

Sink Clogs Are Masked

Clogs in your sink can also go unnoticed when a trap is lacking since the backed up water doesn’t come into the sink but rather goes into the dishwasher where you may not see it.

Leaks may also form under the dishwasher as a result since most appliances cannot handle “flooding” of the dishwasher drain pan. The water supply in the washer is regulated to be only what the appliance can discharge without overflowing. When over filled, the unit will leak, especially around the appliance door seals.

High Loop Installation Methods

Option #1

Clamp Hose To Cabinet Top

Option #2

Run Hose Through Top Of Cabinet

What If I Don't Wanna?

Common Results

  • Bad Odors In Dishwasher And From Sink Drain
  • Leaking Dishwasher
  • Worsening Sink Clogs From Masked Onset Of Leaks
  • Clogs In Dishwasher Drain Hose From Waste Backflow

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