How to Drain a Dishwasher

The dishwasher is connected to a drain hose that runs water into the pipes under or into your sink. Sometimes the plumbing connections in your sink begin to deteriorate and need to be replaced. Or there may be excess debris clogging the bottom of your unit. When your dishwasher won’t drain, you’ll see water and even bits of food at the bottom of it.

When your problem is that the dishwasher is not draining, there may be standing water in the bottom, on the tub. If you open your dishwasher and find a puddle, try running it again. When a dishwasher gets interrupted for some reason, it may not finish its wash cycle.

If the dishwasher is not draining, you may try forcing it. Hold down the “cancel” button for about three seconds, or the time your model's instructions indicate. The water should then drain after it stops. If standing water remains in the dishwasher after the second cycle, you should take a closer look. Once you have figured out how to drain a dishwasher that's not working, you can focus on what might be causing the problem.

You will require the following tools to repair a dishwasher that isn't draining:

• Screwdriver
• Soft brush, like an old toothbrush
• Wet/dry shop vacuum

Here are the materials you'll need for this project:

• Bucket
• Cup
• Turkey baster
• Towels
• Rag or abrasive sponge

Before you begin any work, cut the power to it the dishwasher at the circuit breaker box. To see what’s going on inside the dishwasher, you’ll need to remove the standing water. This makes the drain accessible when troubleshooting and starting the process of how to drain a dishwasher.

• Empty your dishwasher for a full, unobstructed view.
• Take out the bottom rack.
• Remove the excess water with a cup or soak it up with towels or a turkey baster and sponge. You can also use or a wet/dry shop vac to suction it all out.
• Place a bucket and cloth or paper towels around the dishwasher’s base and on the nearby floor. This prevents water from leaking onto your floor.

While your dishwasher can handle glass, it can break in the process. This may lead to small solid debris moving into the drain pump outlet. If so, you must remove the drain pump and vacuum it out to remove debris. You can then replace the drain pump.

You should be aware of your machine’s specific detergent requirements. Today’s machines use automatic dishwasher detergents to work, which don’t produce suds. Powders are preferred, as too much liquid can be added to the dispenser. The heavier liquid levels cause excess sudsing and inadequate draining. People may also use laundry detergent, rather than dishwashing liquid. You should consult your owner’s manual for detergent recommendations. Here are some tips:

• Problems caused by liquid dishwasher or laundry detergents are easily fixed. Just remove the standing water from the tub and run another cycle with the correct dishwasher detergent.
• A mixture of equal parts baking soda and vinegar may unclog dishwasher drains. Pour the solution into the basket at the bottom and let it sit for 15 minutes. Then, pour hot water down the basket and run the rinse cycle.
• However, the baking soda and vinegar mixture may not be strong enough for tough clogs. Repeated vinegar use — especially when reacting with baking soda — may gradually wear down appliances’ metal pipes and rubber seals. This mixture also produces salt, making corrosion worse.
• If is not draining, avoid using drain cleaner for the dishwasher drain hoses. These cleaners leave behind harmful residues and damage plastic and rubber components, like seals. This can lead to leaks and destroy the dishwasher.

If your dishwasher won't drain, check the connected drain hose. This lightweight, corrugated plastic hose connects the dishwasher drain pump to the garbage disposal or sink drainpipe. It can wear out over time, as sediment builds up and restricts flow. There can also be installation issues, leading to kinks and draining issues. Visually inspect your dishwasher to find any drain hose problems and replace if needed. To repair a dishwasher draining issue, you may only need to clean the drain hose, often without its removal.

• Check that the drain hose is properly secured to the sink or garbage disposal and free of food or debris.
• Inspect the bottom of the dishwasher tub for food and waste buildup. You can clean the area with a rag or abrasive sponge.
• You may need to remove the dishwasher drain filter, found at the back or on the tub’s bottom, near the spray arm. While newer models have smaller, built-in grids, debris may still build up. Unscrew the casing with a screwdriver and remove the filter.
• Use a soft brush to remove any food or debris, rinse and reinstall the filter.

If the drain hose becomes kinked, water may not properly drain out and can back up. This may be caused from time passing, or from the hose being bent or damaged. To check for kinks, ensure the hose is securely connected to the sink or garbage disposal and clear of any leftover food and garbage. You should also look in the under-sink cabinet, and if kinked, manually straighten out the hose. It's helpful to know how the drain hose connects to the sink drain.

• High loop to disposal: From the dishwasher, the hose enters the cabinet. It loops to the top, held by a chain, strap, string or tape, and connects to the garbage disposal.
• High loop to drain: If there is no disposal, the hose connects to the drainpipe, with a high loop. The connection is found before the drain line’s P-trap, a fitting that keeps out smelly wastewater.
• Air gap to disposal: The hose runs to the cabinet top, connected to a cylindrical, sink-mounted fitting. There’s one branch for the drain hose and one for the garbage disposal. An air gap stops dirty sink water from returning to the dishwasher.
• Air gap to drain: The hose connects to the drainpipe, not the garbage disposal.

If your dishwasher is draining slowly or not at all, a clog from food sludge or debris in the drain hose might be the culprit. Knowing how to unclog a dishwasher can help you resolve this issue:

• Place old towels under the dishwasher and remove its lower front panel. The panel may just snap off, or you may have to remove a screw or two.
• Find where the hose attaches to the drain pump and disconnect it. Consult the owner’s manual if needed.
• Blow through the hose to check for clogs. If air doesn’t pass through, there’s a clog.
• If the clog is located at either hose end, carefully remove it with a screwdriver or a straightened-out wire coat hanger.
• If not located near the end with the pump connection, remove the hose where it connects to the garbage disposal or air gap.
• Do not clear clogs with a plumber’s snake, as their cutting motion can easily puncture dishwashers.

For deeper kinks and clogs, you may have to replace the entire hose, especially if they return in the same spot. Unplug the dishwasher or turn of its power and slide it out from under the countertop. Then, disconnect the old hose from the pump and garbage disposal (or air gap), and attach the new one. Refer to your owner’s manual to ensure you have the right replacement hose and attachment instructions.

Other important dishwasher components may be causing draining problems. If any are faulty, you must replace them immediately.

• The air gap cylinder, connected to the drain pump by the drain hose, keeps water flowing in the right direction. It also prevents wastewater from backing up into the dishwasher. Check to see if it's clean, without interior buildup, and then be sure it is tightly secured.
• You may want to turn on the garbage disposal. Built-in dishwashers typically drain via the garbage disposal. Loud noises may mean you have a clog.
• Inspect the hose clamp, which secures the hose to fittings and prevents fluid leakage.
• The dishwasher water line, a flexible tube with a shut-off valve, connects the appliance to a home’s hot water supply.
• Check out the drain solenoid for damage, loose wires or corrosion. It opens the drain valve, allowing water to leave the dishwasher.

You can take steps to ensure your dishwasher runs properly. Regular use will keep its parts and plumbing in working order and help to avoid having to repair a dishwasher drainage problem. For instance, be sure to rinse your plates clean of food particles before loading them in the dishwasher. Any debris left in the food filter can clog up the drainage system. And always use the proper temperature setting for the dishwasher cycle.

When your dishwasher is not draining, you should be able to identify and fix the problem. However, the repairs may be more than you can or want to handle alone. Whether a simple interior cleaning, faulty plumbing connections or electrical problems, you can contact a professional to fix the appliance. At The Home Depot, you’ll find a professional, licensed plumber to manage the situation.