How to unclog a dishwasher

Why is there standing water in my dishwasher?

There may be a few reasons why your dishwasher won’t drain. The most common source of clogs often comes from a blockage in the dishwasher's filter. Or, you may have an issue with your dishwasher’s air gap, drain valve, drain hose or even your garbage disposal, causing your dishwasher to clog.

Can I force my dishwasher to drain?

Interrupting a dishwasher while its cleaning can prevent it from completing the cycle entirely and lead to standing water in the tub. You can try to remedy this by resetting your dishwasher. If there’s still standing water, then you may need to investigate the issue further.

How to unclog a dishwasher in 5 steps

You can try to unclog a dishwasher by removing and cleaning the dishwasher filter, checking for clogs in the drain pump, inspecting the garbage disposal for obstructions, cleaning the sink air gap and cleaning the drain hose.

Use the following troubleshooting instructions to help you determine whether your clogged dishwasher is something you can fix yourself.

Locate the filter

First, determine if your dishwasher has a removable filter. Check your owner’s manual to be sure. To find the filter assembly, remove the bottom dish rack and look in the bottom of the tub. In some models, the assembly is located in a back corner, while in others it’s somewhere near the base of the spray arm.

Remove the filter

The filter is often covered by a cage or grille. You can typically remove the dishwasher filter by hand, but some models require a screwdriver. Check your owner’s manual to be sure.

Once the covering is out of the way, you can pull out the filter. If yours has become clogged, you’ll probably see food particles, soil or other visible debris caught in the fine mesh.

Rinse and replace it

You can rinse most of the soils away by simply running the filter under the sink faucet. Scrub caked-on debris away with a soft brush, like an old toothbrush. But don’t use anything made of a tough or abrasive material because you might damage the filter.

Replace the clean filter when you’re done, and fit the cage or grille securely back in place.

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Check inside the drain pump

Sometimes glass can break while in the dishwasher, which can lead to small solid debris getting into the drain pump outlet. Remove the drain pump and vacuum out the area to remove possible debris. Then, replace the drain pump.

Check the garbage disposal

Built-in dishwashers typically drain via the garbage disposal so if your dishwasher is still clogged, this may be the culprit. Turn on your garbage disposal to clear away any leftover food. If you hear a loud sound after turning on your garbage disposal, it may mean your garbage disposal is clogged and you’ll need to troubleshoot that as well.

Have you recently installed or serviced your garbage disposal? Check to see if the knockout drain on the dishwasher was removed. This sometimes neglected step is a common misdiagnosis of a clogged dishwasher.

Clean the sink’s air gap

A dishwasher’s air gap lets air into the dishwasher so it can properly drain without creating a vacuum. Located on the top of the sink, it doesn’t allow anything except for air to come through. However, this air gap may become clogged or blocked and can cause drainage problems in your dishwasher. If you notice any buildup in the sink’s air gap, clean it out and make sure it's tightly secured.

Clean the drain hose

Check your drain hose to make sure it is properly secured to the sink or garbage disposal. The drain hose connects the dishwasher to your garbage disposal or sink and is either located under the sink or behind the dishwasher. If it is properly connected, make sure it is cleared of food or debris. You can clean your drain hose using a drain cleaner solution or you can make your own. Baking soda and vinegar is commonly used as a natural drain cleaner and can be a great solution for weaker clogs. However, you may want to use a stronger drain cleaner for clogs that need to be dissolved right away.

Have you recently redone your kitchen plumbing? An improperly installed drain hose during a remodel is a common cause for the dishwasher not draining. Drain hoses can kink during an installation and can cause the pump to not drain. Sometimes a drain hose has a built-in check valve for one way flow and is installed backward. If the dishwasher was self-installed, make sure to follow the recommendation to replace the drain hose. An old drain hose can accumulate a build-up of sediments, which restricts flow.

Tips to help prevent dishwasher clogs

Make sure your dishwasher is cleaned and regularly maintained to help prevent dishwasher clogs. This includes, but is not limited to:

• Removing large pieces of leftover food from dishes before loading the dishwasher. 

• Choosing a hot water cycle on the dishwasher.

• Wiping down the exterior and interior of the dishwasher and any other parts you can access.

• Regularly checking and cleaning the dishwasher filter.

• Running the dishwasher often and always using dishwasher detergent (never dish soap).

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