How to Fix a Dishwasher with Drainage Issues: Troubleshooting & Solutions

• Take out the dishes and disconnect the power. Then, soak up the standing water inside the dishwasher with towels so you can access the parts.
• Remove and clean the filter with warm, soapy water to get rid of food debris and buildup.
• Check the drain hose for kinks and blockages. If the drain hose looks damaged, you may need to replace it.

Remove any dishes and cut the power.

You need full access to the dishwasher, so take out the dishes. Just place the dishes in the sink for now. It's also important to turn off the power before you start troubleshooting to avoid electrical shock. Just unplug the dishwasher or shut off the circuit its connected to and you're ready to go.

Soak up standing water with towels.

Spread towels on the ground around the dishwasher to catch spills. If the standing water is pretty deep, it'll be faster to scoop it out with a cup and then soak the last of it up with towels. If you have a wet/dry vac, you can use that instead and get the job done a little faster. If you'd like, spread towels on the floor around the dishwasher to catch splashes or spills.

Clean the drain filter and drain.

The circular filter is in the bottom center of the dishwasher. The filter may be covered with fine mash. Every filter is a little different, but the removal process is basically the same—lift it straight up out of the dishwasher. Then, scrub the filter thoroughly with hot, soapy water and put it back in place. The drain (also known as the sump) is the hole beneath the filter in the bottom of the dishwasher. Put on a pair of gloves and clean out the drain with your fingers. Remove solid chunks of food and any other debris inside it. If you’re having trouble identifying the dishwasher parts, check online for your model number and download the user manual.

Clean out the air gap cylinder.

Air gap buildup is common with Bosch and Whirlpool dishwashers. You can find the air gap mounted right next to your sink faucet. It looks like a raised cylinder or knob. Remove the small cylindrical covering to access the air gap (which is usually white). Remove any built-up grime you see with tweezers or an old toothbrush, then pop the cylinder back into place. Your plumbing may not feature an air gap, so don't panic if you don't see one.

Run the garbage disposal.

A garbage disposal clog may be causing your drainage issue. Most dishwashers are connected to the garbage disposal. To see if your garbage disposal is causing the problem, just turn it on like you normally would for about 60 seconds to clear away any leftover food. If the garbage disposal makes unusually loud sounds and struggles to function normally, try cleaning out your drains.

Check the drain hose for kinks.

The drain hose connects the sink drain to the dishwasher. You’ll see the hose underneath the sink running between it and the dishwasher. Use a flashlight to follow the hose to the drainage area. If you see any bends or kinks in the hose, straighten them out with your fingers. You may need to remove the kick plate on the front of the dishwasher to access the drain hose.

Remove the drain hose and clean it.

A drain hose blockage can cause standing water in your dishwasher. Disconnect the hose and scrub the inside with a long, flexible brush to clear away any clogs. Reconnect the hose when you’re done. If the drain hose or connection points look damaged, you may need to replace the drain hose altogether. Be sure to put the drain hose back in place when you’re done! Otherwise, water will go all over the place when you turn the dishwasher on. Also, make sure you install a high loop in the drain hose under the sink to ensure proper draining of the dishwasher. If you aren't comfortable with this, call a professional plumber or appliance technician to install this for you.

Run the dishwasher on a short cycle.

Test out the dishwasher to see if you’ve fixed the issue. Once you’ve troubleshooted everything, run a new wash cycle without any dishes inside. Pick the shortest cycle so you won't have to wait long. Then, open the dishwasher and check for standing water. If your dishwasher is pretty dirty after having standing water in it, pour 3 cups (710 ml) of white vinegar in the bottom before you run the dishwasher using the hottest cycle. A very small amount of water in the bottom of a dishwasher is normal. If the water is still deep and won’t drain, a faulty drain valve may be to blame. Working on the drain valve is best left to a professional, so call a plumber for assistance.