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Fixing Bosch Dishwasher Draining Issues

Updated on October 23, 2017
Paul Edmondson profile image

I found dirty water pooled inside our Bosch dishwasher: Here's how I repaired the problem and a DIY troubleshooting guide for fixing yours.

See that pool at the bottom? Our Bosch dishwasher was not draining.
See that pool at the bottom? Our Bosch dishwasher was not draining.

Bosch Dishwasher Not Draining

After our built-in Bosch dishwasher ran a washing cycle, the bottom of the dishwasher was still full of dirty, free-standing water.

Here's how it's supposed to work: There is a drain pump in the dishwasher that pushes the water out through a drain hose which typically runs from the dishwasher to either the sink's garbage disposal or the air gap. (Our air gap fits on the top of our sink. From there, another hose connects to the garbage disposal.)

If your dishwasher is not draining, something along this pathway is blocked or broken. Here are the troubleshooting steps to take:

1. Check the Filter Inside the Dishwasher (Before Checking the Air Gap or Detaching the Drain Hose)

There is a screen in the dishwasher that is supposed to block large debris from going into the drain hose, but sometimes pieces of food get through and clog the hose. The video below shows you how to check and clean the filter. If you find a big piece of food or glass, remove it and then run the rinse cycle to see if the dishwasher drains. If it still doesn't drain, move to the next step.

2. Check the Air Gap for Clogs

The most common problem that prevents a Bosch dishwasher from draining is small bits of food caught in the air gap. Luckily, this is very easy to fix.

  1. Locate your air gap. It's usually a little hood or cylinder at the back of your sink.
  2. Remove the cover. Most just unscrew or pop off by hand, but some have a small screw that holds it in place.
  3. The top of the air gap has a small piece that can be removed by depressing the small hooks. Remove the top and clean out anything clogged inside.

How it's supposed to work: Water is pumped from the dishwasher up through the air gap (that's the built-in plastic tube) and then usually down through a larger hose to the garbage disposal. The problem is that when the water hits the top of the air gap, small bits of food get stuck between the plastic lid and the built-in tube. This prevents the hose from working efficiently so the dishwasher doesn't completely drain. It's amazing what a huge problem a tiny bit of food can cause.

If you remove a bunch of debris, the problem is likely solved. Run the dishwasher on the rinse cycle and see if all the water is pumped out.

If not, proceed to the next step.

Pull the cover off your air gap and check for debris and tiny bits of food.
Pull the cover off your air gap and check for debris and tiny bits of food.

3. Check the Drain Hose for a Clog

To detach a drain hose from the air gap, you'll need...

  • a bucket to hold the water that will run out of the hose
  • screwdriver to remove the drain hose from the air gap
  • pliers

Using a screwdriver and the pliers, disconnect the drain hose that is attached to the air gap and empty the water to see if the hose is blocked.

To see if the drain hose is blocked, run the dishwasher on the rinse cycle again and hold the hose over the bucket. If the dishwasher doesn't drain, then the drain hose is blocked.

If the hose is obstructed, you might try to use a hanger to push out the clog. However, most drain hoses connect behind a wall and the dishwasher may have to be removed fully to inspect the drain hose. At this point, it's likely that a plumber will need to be called.

Air Gap Disconnected fro Drain Hose and Garbage Disposal

This is the air gap once it's been disconnected from the drain hose and the garbage disposal
This is the air gap once it's been disconnected from the drain hose and the garbage disposal

Questions & Answers

  • What is the check valve on drain hose and what does it do?

    A check valve is sometimes used in place of an air gap. Its purpose is to prevent water from flowing back in the opposite direction.

  • My Bosch dishwasher keeps coming up with either "E18" or "E14" on the display. It did not empty and had a large pool of water in the bottom. Any suggestions?

    These errors aren't associated with a draining issue, but rather a flow issue and a water level issue. Likely something is preventing enough water to flow in to the dishwasher.

  • What is Bosch e23 code?

    An e23 error on a Bosch dishwasher is an electrical problem with the drain pump. It may require replacing the drain pump.

© 2010 Paul Edmondson

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    • profile image

      tom 3 weeks ago

      Alan,

      I don't have an air gap either. There is a large plastic hose from the dishwasher to the disposal. The water pools in the drain below the filter and can smell quite bad if the washer is not used. HOw can I get the water to drain out. Thanks, Tom

    • Paul Edmondson profile image
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      Paul Edmondson 5 weeks ago from Burlingame, CA

      @Alan if it's not completing the cycle, that's likely a different issue where the water in the bottom is a symptom.

    • profile image

      Alan 5 weeks ago

      Paul, thanks for the info. It sounds like you're saying to Paul that it's normal for there to be a little pool of water in the very bottom sump between cycles? There are 1 or 2 cups in mine. I can't decide if that's normal or not.

      Our Bosch gets stuck at various points in the mid rinse cycle and I'm trying to determine if it's a pump issue or not.

    • Paul Edmondson profile image
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      Paul Edmondson 6 weeks ago from Burlingame, CA

      @Glenis, A little moisture is fine and if you clean the filter that should prevent it from smelling. You can also leave the door slightly cracked open and that will help as well. I don't think it impacts the dishwasher, but the newest models do have a different drying feature. I think it's more of a perception issue.

    • profile image

      Glenis Rix 6 weeks ago

      A Bosch dishwasher is a fairly new addition to my kitchen and I had the same concerns as Jerry, so your response to him has set my mind at ease to some extent. But I'm concerned that if I'm away from home for an extended time (e.g. vacation) and therefore not using the machine regularly the stagnant water might breed bacteria and start to smell unpleasant. I'm wondering if incomplete drainage a design fault?

      P.S. I take out the filter once each week to rinse it ( as per my instruction manual) and run a cycle with dishwasher cleaning fluid every few weeks.

    • profile image

      Easy Fix for Bosch dishwasher error code E24 6 weeks ago

      Thanks! When I took it off the trap the drain line had water in it up to the top. I went and got a garden hose and I flushed water back into the dishwasher (take off mesh filter first) and gunk did come out. I have a hand pump that small boat owners use to pull the water back out of the dishwasher. Runs great now. It was great to not have to take off any hoses or having to pull out the dishwasher. Thank You!

    • profile image

      Canyon Jim 6 weeks ago

      I have a 2002 Bosch DW SHU5305UC/UC12 that quit draining. It works fine otherwise.

      I have a high loop in my drain hose instead of an airgap.

      My hoses allow air to pass in and out so I don't thibk they're clogged. The back flow tab ob the drain system did breakand was removed. Will that prevent the unit from pushing drain water to the outlet in my disposal? If it shouldn't, what else should I check? The motor runs and the pump pumps the water, it just won't go out of the pump into the disposal outlet. I woulsd apreciate input before I decide to junk it or spend more money. The flap isn't expensive, but if something else is invovled I'd like to determine those costs before spending time and money on the unit.

    • Paul Edmondson profile image
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      Paul Edmondson 7 weeks ago from Burlingame, CA

      @Sue Sometimes the disposal can back up and water will come out of the air gap. It's also possible the line from the air gap to the disposal is blocked. First, run the disposal and try running the washer on a rinse cycle to see if that fixes the issue. Next, check the line from the air gap to the disposal. It's rare, but you can also try replacing or bypassing the air gap.

    • profile image

      Sue rans 7 weeks ago

      I have a Bosch dishwasher and the air gap has dirty water after each wash I check and clean air gap but the same thing happens again. Any idea what could be the problem? Thanks

    • Paul Edmondson profile image
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      Paul Edmondson 2 months ago from Burlingame, CA

      Sometimes they wear out and need to be replaced. If a dishwasher lasts over 10 years that's pretty good. It seems like the more electronic parts they add, the shorter they last. My previous Bosch lasted over 20 years I think.

    • profile image

      Emma Foulkes 2 months ago

      I can't get my dishwasher to work. It started with dirty water in the bottom so I scooped it out, then cleaned the trap and filters, then checked the hose under the sink and I don't have an air trap. I've tried resetting it too but nothing is working. I've no idea what else to do!

    • Paul Edmondson profile image
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      Paul Edmondson 2 months ago from Burlingame, CA

      @Holly disconnect the hose from the sink and run the rinse cycle with the hose in a bucket. If there isn't water, try a hanger to unclog it before removing the hose since that requires pulling the dishwasher out.

    • profile image

      Holly 2 months ago

      Bosch dishwasher not draining. I have already checked the filter and removed the screw to make sure that the propeller is moving. And replaced this cover. I don't have an air gap on the countertop. Should I remove and check hose where it attaches in under the sink? Any help would be appreciated

    • profile image

      Jerry Hunter 2 months ago

      Thanks for your quick response Paul. This alleviates my worries regarding the dishwasher draining properly. First time on this site but I'm book marking it in case I have further problems. Thanks so much for helping us "Dishwasher Challenged" people and saving us those dreaded service calls.

    • Paul Edmondson profile image
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      Paul Edmondson 2 months ago from Burlingame, CA

      @jerry as long as there isn't any water in the pan, it should be fine. A small amount of water inside where the filter fits is normal. If it's pooling in the pan, then there is an issue. Also remember Bosch dishwashers can have moisture after the cycle completes - that's normal as well. However new Bosch Dishwashers have a new "dry" feature.

    • profile image

      Jerry Hunter 2 months ago

      When our Bosch dishwasher Mod. SHUY3C02US finishes a wash I still find a small amount of water when I remove the filter. Is this normal or is it not completely draining? Thanks in advance.

    • profile image

      Roy Schmoll 3 months ago

      Thanks Paul. Air-Gap - eh. Solved my issue.

    • Paul Edmondson profile image
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      Paul Edmondson 3 months ago from Burlingame, CA

      Martha, glad it helped. If you have a newer Bosch and a garbage disposal, I'd consider rerouting the line and skipping the air gap. It's not really necessary. I just put in a new dishwasher and decided to do this. It's works great.

    • profile image

      Martha 3 months ago

      Thanks so much, we've had 2 repairmen come out, and neither even checked the air gap! I was able to unclog it in 5 minutes thanks to your post. Not only did it stop the water from pooling, but my dishes are much cleaner.

    • profile image

      zen 6 months ago

      i have a bosch dish washer its just taking the water and after filling its drain out ..may i know what is the problem .

    • Paul Edmondson profile image
      Author

      Paul Edmondson 6 months ago from Burlingame, CA

      I had a new Bosch installed and my wife was complaining it wouldn't drain. The first check was the air gap and sure enough, a tiny bit of food was stuck in it. It's a bit surprising how such a small amount of food can cause a clog. The good news is it's super easy to clear.

    • profile image

      bobbrewer 6 months ago

      Thanks Paul, your post is still saving people money. such a simple fix.

    • profile image

      Jeff 6 months ago

      Awesome, the air gap was clogged on mine, unclogged and it works - thank you!!

    • profile image

      J925 9 months ago

      Great tips! Thank you so much! I have been wondering why my dishwasher does not drain completely in the past 3 weeks. The air gap was clogged!

    • Paul Edmondson profile image
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      Paul Edmondson 12 months ago from Burlingame, CA

      Jesse, I'm glad it worked well!

    • profile image

      Jesse S 12 months ago

      Hey Paul,

      Thanks for the info - worked great, saved me time & $$$. Tried option one (dw drain filter), which turned out not to be the problem. It was option 2, a clog in the airgap filter - nasty: salmon bones and other gunk! It was such an easy fix. Love not calling repair men. Feeling the DIY love bro!

      Coincidently, I graduated from Cal Poly Pomona in 1970 with a degree in Management Information Systems - the early days of the computer age - never a dull moment.

    • Paul Edmondson profile image
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      Paul Edmondson 12 months ago from Burlingame, CA

      I guess it's possible that the air gap is built in. Look up the model to see or call the appliance store and ask. It could have been installed incorrectly. The air gap is what prevents water from back washing into the dishwasher. It's possible the lack of an air gap is the problem.

    • profile image

      Kristina 12 months ago

      What if you don't have an airgap? Have a brand new Bosch with the line running to the garbage disposal and it always has a few inches of standing water, which winds up smelling wretched between cycles.

    • Paul Edmondson profile image
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      Paul Edmondson 13 months ago from Burlingame, CA

      @krista I always love to hear that this helps people fix it themselves. Thank you!

    • profile image

      Krista 13 months ago

      Thank you so much - it was clogged air gap, and you just saved me $100 trip fee.

    • profile image

      Ash 14 months ago

      You Rock! Thanks! I was on the last step and sure enough round the clog

    • profile image

      Jodi 17 months ago

      it worked!!! thanks a million!

    • profile image

      Jennifer 2 years ago

      Just cleared the air gap, carrots! Thank you! No more standing water.

    • profile image

      Ralph 2 years ago

      Thank you for the great advice. I wish I had found your post earlier. I just finished running the dishwasher and there is no water left in the bottom. Thank again.

    • profile image

      Celine 3 years ago

      I have the suds problem with my bosch dishwasher. Have had three different repair companys look at it. They all try to blame me . Getting a fourth repair man to try to fix it. Ladies, look in your dishwasher as soon as it finishes the cycle to see the suds. Or they go away after a short time.

    • Paul Edmondson profile image
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      Paul Edmondson 5 years ago from Burlingame, CA

      Hopefully this is a bit more clear on how to remove the clog. Let me know if the instructions aren't clear.

    • profile image

      Davidrwells 5 years ago

      I had same problem with my dishwasher as well but I called a plumber and he charged me heftily for a minor repair like that. At that time I didn't know I could do it myself but thanks to you I won't be spending my hard earned money on plumbers again.

    • profile image

      jdh 5 years ago

      Amazing - this took care of my problem and just in time to avoid the repair man... Took me 45 min and saved me some time, trouble, and money bringing in a repair man.

    • profile image

      darlenebb 5 years ago

      Great comments and helpful I am off to pursue fixing mine. I have water at the base of it and od not want expensive repair costs.

    • profile image

      Melanie 5 years ago

      Great post. I used my steam vacuum cleaner to suck the water out of the dishwasher and then to suck water out of the drain hose. A bunch of pumpkin seeds came out. I did not put any pumpkin seeds into my dishwasher. They must have come from my garbage disposal. It's always a good idea to run the disposal before running the dishwasher. I do not have an air gap, most likely because my dishwasher was installed by some folks who are less than professional -- my dad gave me the dishwasher as a gift and used his people to install it, not professionals, such as you would get if you bought directly from Lowe's or Sears. Anyhow, these folks have done other jobs at my house, and their lack of knowledge regarding codes is astounding. They "repaired" a backflow preventer on my sprinkler system by installing a cheapo non-backflow preventer connector. Guess what? I soon had "air hammer," loud knocking in my walls. When I insisted that they do the job over with an backflow preventer that I purchased, the knocking went away. They also installed a microwave too close to the stovetop, so they had to redo it, and now I have two huge holes in the tile underneath my microwave. Beggars can't be choosers, and all of this was my dad's gifts to me, but I'd rather not have my house burn down due to code violations on a microwave or poison my family with backflow from my yard entering my drinking water supply. And now this! Yikes. I guess I need to install an air gap myself, or always remember to run the garbage disposal before running the dishwasher. Thanks for walking me through this!

    • profile image

      DM 5 years ago

      Great post. It saved me a call to a repair man.

    • profile image

      Dave P 6 years ago

      Just cleaned ours out and found some pumpkin seeds! Thanks for the helpful post!

    • profile image

      plumbing 6 years ago

      Above all method of unclogging the drainage, removing the blockage physically is the most effective one. It is a long term solution for clogged drainage that homeowners should try at home to avoid spending bucks of money.

    • profile image

      br14nwll 6 years ago

      Good Job, Paul! It is best to try to troubleshoot the problem first before calling a repairman.

    • sheila b. profile image

      sheila b. 7 years ago

      I once peeled carrots in the sink and then removed all but the tinyist little bits. Those got washed down the drain. And clogged it. Love carrots, but handle with care! And I'm impressed with your skill. First, you have to know what you're looking at, and what it does. Way beyond me!

    • GojiJuiceGoodness profile image

      GojiJuiceGoodness 7 years ago from Roanoke, Virginia

      Very Good info! I've never had this problem, but it's likely to happen sooner or later. :)

    • John B Badd profile image

      John B Badd 7 years ago from Saint Louis, MO

      These are some great tips.

    • Paradise7 profile image

      Paradise7 7 years ago from Upstate New York

      Good hub, I had a dishwasher with the same problem. We kept having to call the repairman, because neither of us knew how to fix it. Finally, we just resumed doing dishes by hand.

    • Drax profile image

      des donnelly 7 years ago from NYC....

      this reminds me of Billy Connolly, the Scottish comedian, where he talks about vomit and asks how come it always contains carrots... even if you have not eaten any...

      OMG, they are like Triffids, they are attacking dishwashers... ;-)

    • abrarr profile image

      abrarr 7 years ago from USA

      that was a good hub regarding dishwasher problems and their maintanence.

    • 2patricias profile image

      2patricias 7 years ago from Sussex by the Sea

      Prevention is better than cure: scrape the plates before putting them in. However, it can be beyond difficult to train all members of the family to do so.

      Congrats on fixing this yourself.

    • ethel smith profile image

      Eileen Kersey 7 years ago from Kingston-Upon-Hull

      Well done you. These jobs often turn into huge expensive ones

    • Psalmist4M profile image

      Psalmist4M 7 years ago from the Shelter of His Wings

      Great information. It helps to have the information from someone who has experienced it first hand. Even the responses & comments are helpful advice and appreciated. Thanks for sharing.

    • Hello, hello, profile image

      Hello, hello, 7 years ago from London, UK

      To avoid all this rinse you dishes before you put them into the dishwasher. Thank you for pointing our the trouble and how to deal with it.

    • LillyGrillzit profile image

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

      Thank you for letting us know the problems with draining in a dishwasher.

    • gredmondson profile image

      gredmondson 7 years ago from San Francisco, California

      Some plumbing codes insist on air gaps, the purpose of which is to prevent water from the drain, or garbage disposal in Paul' case, from back flowing into the dishwasher. There are other devices besides air gaps that perform the same function. One of the reasons air gaps get clogged is that the filter screen will not be secured properly in the bottom of the dishwasher.