dishwasher not draining

What Is A Dishwasher High Loop? (Is It The Best Option?)

A dishwasher high loop is when the drain hose is elevated up before it’s connected to the sink. This is important to have done correctly or else the sink will drain into your dishwasher.

What is a Dishwasher high loop?

The dishwasher high loop prevents water from draining the wrong way. If the drain hose isn’t elevated, the wastewater from your sink could potentially drain to your dishwasher. This will lead to having standing water in your dishwasher. 

The slope of the high loop creates an air gap that prevents back flow from occurring. The waste that was not able to make it to the dishwasher will drain back into the sink or the garbage disposal. If a clog occurs, this makes it easier to handle. A clog in a dishwasher is a lot harder to deal with than a clog in a sink or garbage disposal. This also makes it less likely there will be a clog in the first place, if it is installed correctly. High loops can be a good method if they are installed correctly and are monitored to make sure they don’t come loose. 

dishwasher high loop
Diagram of a high loop

How To Install A High Loop

Installing the dishwasher high loop as close to the underside of the counter as possible will make it the most effective. Make sure the drain pipe is installed right before the P-trap, but not on or after it. Use a zip tie to secure it in place. A high loop’s highest point needs to be at least 32 inches above the ground. If it’s not possible to do this, you should look into other options.

Is A Dishwasher High Loop the Best Option?

High loops are a good method, but that doesn’t mean they’re the best. A high loop will not assure back siphonage prevention. Water flow can reverse and cause the dishwasher to suction dirty water if the water pressure drops significantly. Also, it’s not always possible to have a 32 inch gap between the highest point of the high loop and the floor. When this isn’t possible, you need to look into getting an air gap.

Air Gaps

Air gaps for your dishwasher are a safer and more effective option than high loops. They are mounted above the sink to prevent wastewater from entering the dishwasher from the drain. This separates the hose so no water will be able to get through. This creates a gap between the dishwasher and garbage disposal. They are installed under the sink, but there is a heading that sits above the sink by the faucet. This heading houses the vertical air gap. Air gaps have holes that release water into the sink if the drain gets clogged. If you have a leak in your air gap, that most likely means there is a clog somewhere in your drain tubes.

dishwasher high loop air gap
Air gap above the sink

Do I Need An Air Gap?

In some locations air gaps are required. If you aren’t required to have one in your location, you should still get one (or consider a high loop). As mentioned previously, air gaps prevent back flow to your dishwasher. This can lead to standing wastewater in your dishwasher. It’s never good to have dirty water build up anywhere in your house, especially around the items you use to eat. A dishwasher is designed to clean your utensils and dishes, but it can’t do this effectively if dirty water is constantly being drained into the dishwasher. We recommend getting an air gap to prevent these issues from happening. 

dishwasher high loop air gap pre installed
Air gap pre installed

Final Thoughts

High loops can be a good and inexpensive option to prevent back flow. Even if they aren’t as effective as air gaps, that doesn’t mean you can’t have success with one. Air gaps and high loops are both good options to prevent back flow from your sink to your dishwasher. These are important to have so you don’t end up with dirty water standing at the bottom of your dishwasher.

Call 1-Tom-Plumber

Don’t hesitate to contact us here or call us at 1-Tom-Plumber (1-866-758-6237) if you need a plumbing service. 1-Tom-Plumber’s certified team of plumbers and drain technicians respond immediately to any emergency plumbing, drain cleaning, or water damage problem. We also handle the excavation of underground water lines and sewer main lines. Our immediate-response team is available every day and night of the year, even on holidays.

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