Why Is My Dishwasher Not Draining?

Updated on January 9, 2018
SteveoMc profile image

I am a retired appliance repairman with many years of experience. I am excited to share with you what I've learned over the years.

Why Is There Water Left in My Dishwasher at the End of the Cycle?

There are several possible causes—some simple and some not so simple.

  • Full garbage disposal
  • Clogged drain
  • Plugged air gap (this device prevents siphoning of sewer or drain water into the dishwasher)
  • Clogged anti-siphon device
  • Bad pump
  • Bad timer

Full Garbage Disposal?

  1. Start by checking the garbage disposal; is it filled with food? It might be blocking the dishwasher drain.
  2. Run the disposal and check if the dishwasher drains properly.

Clogged Drain or Plugged Air Gap?

The next order of business is to determine how much water is left in the dishwasher. It should be filled just below the door seal when it is full. That is about 3 inches of water. If some but not all of the water is gone at the end of a cycle, the problem is most likely in the drain.

The wastewater enters the pump through a screen and possibly through a soft food disposal. Then, it is pumped into a drain hose. The drain hose is most likely connected to an air gap device located on the exterior of a wall, just outside the kitchen, or under a slotted, metal cylinder on the sink beside the faucet. There will be a drain hose going from the air gap to the drain, most likely a garbage disposal. If you do not have a garbage disposal, then it will be connected to the sink drain. I have seen a lot of goofy installations, but these two scenarios are the most common.

Here is how to check the drain:

  1. Run the dishwasher. If water comes out of the air gap into the sink or pours on the ground outside the kitchen, then the drain is plugged at the air gap or in the hose that goes to the drain or garbage disposal.
  2. Remove the drain hose; it will be held in place by hose clamps.
  3. Check for a blockage, clean it thoroughly with a brush or rag on a coat hanger wire, and wash it off with a hose.
  4. Check inside of the air gap outlet to see if something is stuck in there. I have found the most interesting things in the air gap. I am still scratching my head after seeing a ring, a plastic bag, a hair scrunchie, and what looked like a part of a snake. Ewww! Make sure it is clear of debris.
  5. Replace the hose.
  6. Remove the hose from the air gap that comes from the dishwasher.
  7. Place the end of the hose in a bucket. Turn the dishwasher on and let it drain into the bucket. If the water pressure is like that of a garden hose, it is working correctly.
  8. Let it drain into the bucket for a few seconds to give it every opportunity to flush anything left inside the hose.
  9. Check the inlet side of the air gap and make sure that it is free of debris and other blockages.

If you found a clogged hose or air gap, it is now fixed. Run a cycle in the dishwasher to check if the water drains properly. If it does, then the problem is fixed!

Clogged Anti-Siphon Device?

If there is still a problem after cleaning the drain hoses and the screens, a possible problem could be with an anti-siphon device. Only some dishwashers are equipped with these, and they are a nuisance to get to.

The anti-siphon device is located where the drain hose connects to the pump. It typically looks like a small ball in a cage at the end of the drain hose. The ball is drawn toward the drain hose when the pump is pumping water; this opens the drain, and water flows freely. When the pump stops pumping water, the ball floats back to the pump drain blocks it so that no water from the drain or drain hose can enter the dishwasher. If food or other debris gets lodged into this device, the drain may be blocked. It has to come off and be cleaned.

If the anti-siphon device is clear, then the problem at this point is solved.

Front panel view. Your dishwasher is likely secured to the countertop with two screws at each corner above the front panel.
Front panel view. Your dishwasher is likely secured to the countertop with two screws at each corner above the front panel.

Bad Pump or Timer?

If it is a poorly performing pump, only a small amount of water will pump out. If it is the timer it may not pump long enough. Does the pump make unusual or loud noises? If the pump is not working efficiently and making noise, it is probably a bad pump.

Does the timer stop before the end of the cycle, or does it sometimes get stuck during the cycle? Does the timer knob turn hard or skip? If it does not complete a cycle, it is probably a bad timer. Time to replace the timer.

Water and electrical connections. You'll need to remove these to fully remove the dishwasher.
Water and electrical connections. You'll need to remove these to fully remove the dishwasher.

Replacing the Pump:

The pump is an easy job on some dishwashers and very difficult on others. You will need to use the model number to find the correct pump. Depending on the location of the pump, you can determine the difficulty of the job. GE dishwashers are one of the easiest. In any case, the dishwasher will have to come out.

  1. Turn off the power and water.
  2. Disconnect the water supply, the power supply (this is often just a plug), and the drain.
  3. The dishwasher is normally held in place with a couple of screws driven into the bottom of the counter through brackets on the top of the dishwasher. Remove those.
  4. The dishwasher should now slide out, and you can gain access to it.

I would use this strategy to take the dishwasher out and see if you can manage to get the pump out. If it seems easy enough and a job that you can do, then order the new pump. If you cannot figure it out and complete the job, it may be time to get a new dishwasher. A pump assembly can be kind of expensive and with a service call and repair it is probably going to top $200. Time to move on.

The timer mechanism is generally tucked away inside the front panel.
The timer mechanism is generally tucked away inside the front panel.

Replacing the Timer

If you determined it is the timer, then you are in for a thrill! Just kidding. Changing the timer out can be daunting. It is located in the door panel and is sometimes difficult to access. You will have to open up the door. If it is held in place with a spring and pulley system, where you have access to the springs in the front, it might help to unhook the spring so that the door does not keep closing. If the spring is difficult to work with, it would be a good idea to just leave it alone.

Start by removing the hold-down screws in the inside liner. Removing the liner will give you access to most dishwasher timers. Some dishwashers have conveniently installed the timer in a separate enclosure. It is fairly easy to remove the timer and replace it. If you are confused at all along the way, take the time to sketch the assembly out. Be cautious—some dishwashers have some of the mechanisms attached or held in by the front liner.

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    • profile image

      Ayana 22 months ago

      Perfect instructions!! Dishwasher clog fixed...now if I can just figure out why its overflowing with suds.

    • profile image

      Randy 7 years ago

      I bought brushes for my washer at www.pricedrightparts.com and they got them to me the very next day. I loved it. Anyway good article. Thanks for the info.

    • SteveoMc profile image
      Author

      SteveoMc 7 years ago from Pacific NorthWest

      Thanks for the great information.

    • profile image

      dishwasher spares 7 years ago

      The dishwashers in america work in a slightly different way to the UK version, in the uk all dishwashers have a control module and a selector switch to control them, no electrical / mechanical timers anymore. nice to know how the US version works.

    • SteveoMc profile image
      Author

      SteveoMc 7 years ago from Pacific NorthWest

      Maryanne I hope this helps someway. Thanks for stopping by.

    • Maryanne Maguire profile image

      Maryanne Maguire 7 years ago from Santa Monica, CA

      Ours died altogether, so this is a handy checklist for us to start finding the trouble spot(s). Thanks!

    • SteveoMc profile image
      Author

      SteveoMc 7 years ago from Pacific NorthWest

      Lilly Bad bad bad, LOL. It's a machine, you are a person. To heck with the machine.

    • LillyGrillzit profile image

      Lori J Latimer 7 years ago from The River Valley, Arkansas

      Why do I feel guilty everytime I read your appliance Hubs. I have been a Bad Appliance caretaker in the past. Thanks for the conversion!

    • SteveoMc profile image
      Author

      SteveoMc 7 years ago from Pacific NorthWest

      Pampushy I just saved someone $100....it makes me so happy, too bad it wasn't you. Next time....thanks for reading and leaving a comment.

    • profile image

      Pampushky 7 years ago

      I hate when this happens...the first time cost me $100 to have someone come out and unblock the dumb thing...Only a fool once though! Nice article

    • SteveoMc profile image
      Author

      SteveoMc 7 years ago from Pacific NorthWest

      dinesh Thanks for coming by and leaving a comment. I appreciate it.

      ethel Always a pleasure to see you read one of my hubs. Thank you for taking the time to comment.

      Justom Love the humor....LOL You know it, these are just machines, they will give out some day.

      Kelly Logical Are you a nut? What kinda tomfoolery is that comment? And, you don't have to yell.

    • justom profile image

      justom 7 years ago from 41042

      I'm so tired of dishwasher hubs... just kidding but I am tired of washing dishes. I'm saving all these useful hubs 'cause it's only a matter of time before I"ll need them. Peace!! Tom

    • profile image

      Kelly Logical 7 years ago

      hEY ETHEL YOU ARE AWESOME VERY RESOURCEFUL KINDA GAL.

    • ethel smith profile image

      Eileen Kersey 7 years ago from Kingston-Upon-Hull

      Very informative. I shall be back no doubt in the future :)

    • dinesh c bhatt profile image

      dinesh c bhatt 7 years ago from India (Noida)

      Very informative, well written

      Thank you for sharing this

    • Hello, hello, profile image

      Hello, hello, 7 years ago from London, UK

      A well written hub giving good advice.

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