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Dishwasher not draining: what to check and how to fix it

Most drain problems come down to a dirty filter, a kinked hose, or a clog where the dishwasher empties into the sink. Here is how to check each one safely.

Updated · 6 min read

You open the dishwasher after a cycle and find a pool of cloudy water in the bottom. It's frustrating, but it's one of the most common appliance problems, and most of the time the fix is simple and free.

Water leaves your dishwasher through a filter, then a pump, then a drain hose that runs under the sink to the garbage disposal or the sink drain. A clog or a bend anywhere along that path will leave water behind. We'll check each spot in order, starting with the easiest.

Plan on 20 to 45 minutes. You won't need special tools for most of it.

One thing first: a small amount of water in the filter area at the very bottom is normal. Whirlpool says it keeps the seals from drying out and drains at the start of the next cycle. If the water covers the floor of the tub, keep reading.

What you'll need

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If you end up needing a part, find your model number first. Our guide on finding your appliance model number shows where to look.

Bail out the standing water

Lay towels in front of the dishwasher. Pull out the bottom rack. Scoop out the water with a cup, then soak up the rest with a towel or sponge. A wet/dry vacuum makes this faster.

Clean the filter

A clogged filter is the most likely cause, especially if you rarely clean it. Most newer dishwashers have a filter you can twist out from the floor of the tub, usually near the base of the lower spray arm or in a back corner.

  1. Remove the filter. On many Whirlpool models, you turn the upper filter about a quarter turn counterclockwise and lift it out, then pull out the lower filter. Check your manual if yours looks different.
  2. Rinse it. Hold both pieces under warm running water. Use a soft brush on stuck food or hard-water buildup. Don't use a wire brush or scouring pad, since they can damage the mesh.
  3. Check the opening. With a flashlight, look into the hole under the filter for bits of glass, bones, seeds or labels. Pick them out with gloved fingers.
  4. Put it back and lock it. If the upper filter spins freely, it isn't locked in place. Never run the dishwasher without the filters installed.

Restore power and run a short rinse cycle. If the water drains, you're done.

Just installed? Check for the knockout plug

If the dishwasher or the garbage disposal was installed recently, this is the first thing to suspect. New disposals come with a plastic plug sealing the small inlet where the dishwasher hose connects. If nobody knocked it out, the water can't get through.

  1. Turn off the disposal's power. Unplug it or switch off its breaker.
  2. Remove the hose from the disposal inlet. Squeeze or loosen the clamp and pull off the dishwasher hose. Have a towel ready for drips.
  3. Knock out the plug. Whirlpool's installer guidance is to tap the plug into the disposal with a screwdriver and hammer, then pull the loose piece out from inside the disposal with needle-nose pliers.
  4. Reconnect the hose. Slide it back on and tighten the clamp.

If you're not comfortable doing this, it's a quick job for a plumber or the installer who set it up.

Run the garbage disposal

Many dishwashers drain through the disposal. If the disposal is full of food, the dishwasher water backs up. Run cold water and turn on the disposal for a bit, then try a rinse cycle. If the disposal hums or won't turn, see our guide to a garbage disposal that's not working.

Check the drain hose for kinks and clogs

With the power off, open the cabinet under the sink and find the ribbed hose coming from the dishwasher.

  1. Look for kinks. A hose pinched behind stored items or bent sharply during installation can stop the flow. Straighten it and move anything pressing on it.
  2. Check the high loop. Most installation instructions have the hose rise up high under the counter before it drops to the drain, or connect to an air gap. This keeps dirty sink water from flowing back into the dishwasher. If the hose sags low along the cabinet floor, the dishwasher may refill with drain water.
  3. Check for a clog. Loosen the clamp, pull the hose off the disposal or drain fitting over a bucket, and look inside. Flush it with water from the sink sprayer if you can.

Rules about air gaps and high loops vary by city and county. If you're not sure your setup is right, a plumber can tell you what your local code requires.

Clean the air gap

Some sinks have a small chrome or plastic cap on the countertop near the faucet. That's the air gap. If water spurts out of it during a cycle, it's clogged. Pull or twist off the cover, remove the inner cap, and clean out the gunk with a small brush. Put it back snugly.

When to call a pro

Stop and call for repair if:

  • The filter, hose, air gap and disposal are all clear, but water still won't drain. The drain pump or its motor may have failed, and a technician can test it.
  • You hear humming or grinding but no water moves.
  • You see water leaking under the dishwasher or onto the floor.
  • You smell burning or see scorch marks.
  • You rent your home. Check with your landlord before you take anything apart.

Not sure which way to go? Try our fix it or call a pro quiz, or read how to choose an appliance repair technician.

Keep it from happening again

  • Rinse the filter about once a month, or every two weeks if you run the dishwasher daily.
  • Scrape bones, seeds, labels and large food scraps into the trash before loading.
  • Run the disposal before you start the dishwasher.
  • Keep stored items under the sink from crushing the drain hose.
  • Use only dishwasher detergent. Regular dish soap makes too many suds.

Common questions

Is a little water in the bottom of the dishwasher normal?

Yes. Whirlpool says a small amount of standing water in the filter area is normal. It keeps the seals from drying out and drains when the next cycle starts. A pool that covers the floor of the tub is not normal.

How often should I clean the dishwasher filter?

Whirlpool suggests rinsing the filters about once a month, or every two weeks if you run the dishwasher every day or have a large household. Your owner's manual has the schedule for your model.

Why won't my brand-new dishwasher drain?

If the dishwasher or the garbage disposal was just installed, the knockout plug inside the disposal's dishwasher inlet may still be in place. Water has nowhere to go until that plug is removed.

Can I use drain cleaner in my dishwasher?

No. Chemical drain cleaners can damage dishwasher parts and are dangerous if they splash back. Clear clogs by hand, by cleaning the filter, or by having a technician check the pump.

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