Why Does Your Dishwasher Gurgle When Draining

A common issue many homeowners face is a gurgling sound when their dishwasher drains, especially if the appliance is newly installed. While not a major concern right away, the gurgling noise can be quite loud in some instances, prompting the need for a resolution that silences the noise. A gurgling sound could be a warning that a more serious issue is about to present itself, so you need to get to the bottom of the noise sooner rather than later. 

In this short guide, I will go over why dishwashers gurgle when draining and what can be done to remedy the situation. 

What Causes the Gurgling Sound

Gurgling sounds in plumbing and plumed appliances occur when air rushes over or through standing water within the pipes or appliance. In the case of a dishwasher gurgling, water is likely standing somewhere in the drainage system, and when the fast-moving water exits the appliance, a gurgling sound can be heard as the water drains. 

Dishwasher Makes Gurgling Noise When Running

There are a couple of reasons a dishwasher might make gurgling noises when running. 

Clogged Drain or Hose

Even though dishwashers have filters to catch most of the food debris that rinses off the dishes, some food particles still make their way into the drain and drain hose. As food particles pass through, they can accumulate in the drain or hose, usually in the low points, narrowing the flow inside the hose. 

The gurgling sound occurs when the drain water rushes past these blockages on its way out of the appliance. 

Drain Hose Position

If the drain hose is excessively long it can have several loops creating high and low points. Water can gather and sit in the low points and move under air pressure when the dishwasher is running. This movement can open and close pockets of air in the hose causing the gurgling noises you hear whilst your dishwasher is running. 

Sink Gurgles When Dishwasher Drains

In some instances, you may find that the sink makes a gurgling noise when the dishwasher drains. There are several reasons for this, so let me explain each and offer guidance on how to resolve it.

Air Gap Issues

An air gap is a small device typically installed on the sink or countertop near the dishwasher. It serves as a physical barrier between the dishwasher and the sink drain. The purpose of the air gap is to prevent contaminated water from the sink or garbage disposal from flowing back into the dishwasher. It creates a gap of air that acts as a buffer, ensuring that only wastewater from the dishwasher is drained.

If the air gap gets clogged with any type of debris or mineral deposit, it will disrupt the water flow resulting in the all too familiar gurgling sounds. It’s important to regularly maintain the air gap clean and free from obstructions. To clean it remove the top cap, clear any debris, and then rinse it thoroughly. Once you have cleaned it, reassemble it as before. 

Venting Problems

You should think of your household plumbing as a system or a network of pipes. The entire plumbing system needs to be vented to allow sewer gasses to escape outdoors protecting you and your family from the noxious fumes. 

Dishwashers are also connected to this venting system, and sometimes the vent pipe can be blocked by fallen leaves or even a nesting bird. If this happens, the gasses in the system can’t escape and build up in your plumbing system and produce gurgling sounds, as air and water move under pressure. 

If you suspect this to be the cause of your gurgling issues, get it fixed quickly as it can soon lead to more serious problems.

Plumbing Issues

The gurgling sound you hear when your dishwasher drains may not be a dishwasher issue at all. Instead, it could be a problem somewhere in your home’s plumbing system. There could be a blockage in a secondary drainpipe on the bathroom, or toilet pipes, or worse, in your home’s main drainpipe. 

Partial blockages in the drain pipe or an incorrectly installed drain line can lead to water flow issues, causing gurgling noises during dishwasher operation.

If this is the case, it is best to schedule an appointment with an experienced plumber to diagnose and fix the issue. 

When to Call For Professional Assistance

Figuring out why your dishwasher gurgles when draining can be an easy fix, especially if the cause is something like a blocked drain or improperly positioned drain hose. If the cause is something more involved such as venting or plumbing problems, I recommend calling for professional assistance. These more serious issues can involve climbing on the roof or digging up the backyard, so it is best to leave it to the experts. 

Check out 8 Reasons Your Whirlpool Dishwasher Is Not Drying Dishes

Appliance Service Technician | Website | + posts

Andy has over 8 years of experience working on residential household appliances, performing diagnostics, and repairs across most major brands. He graduated from the Denver Institute of Technology, is NASTeC certified, and has worked for Mr. Appliance. Andy has contributed to features on major publications including Better Home & Gardens, Family Handyman, and Yahoo.com.