Terry Caliendo

ON March 26, 2014

Bosch Dishwasher Not Draining, Leaving Standing Water after the Wash Cycle Completes


About 2 weeks ago we noticed that after the dishwasher finished its cycle, there was a larger than normal amount of standing water in the bottom.  There's always been a little bit of water that remained to be found when I'd pull the filter out to clean it, but this was as few inches above that filter at the bottom of the washer.

Never wanting to pay a repair person money to come over and fix something obvious, I set out to see if I could solve the issue on my own. My first thoughts were that either the drain tube was clogged or the drain pump was fried.

Looking in at the bottom of the washer, I saw what looked like a float and reasoned it was probably a safety device, such that if the water fills up to high inside, the float rises, turns on the drain pump, and the water gets flushed out.  As the remaining water in the bottom of the washer wasn't high enough to float the float and trigger the pump, I pulled up on the float to see what would happen (in the picture below, I had already manually drained the standing water).

Bosch Dishwasher Safety Float Switch

After pulling the float up, I heard a couple relays click in, but after that, nothing happened. I didn't know for sure that anything should happen, but it seemed like it should as relays are used to turn on high powered devices like pumps.

So I started taking the washer apart so I could see if I could find the drain pump.

Bosch dishwasher with front panel removed

On the inside of the door there are a bunch of screws that hold the front panel on.  I removed them and learned the hard way that you only need to remove the bottom screws because top screws hold the control panel on, which is a separate piece.

After removing the front panel, I was able to remove another cover at the bottom where I could see some inner workings of the machine.

Bosch diswasher lower front access to drain pump

The first thing I saw was the hose and motor in the center of the above picture, which are right below the filter and thus would seem to be a drain tube and a pump.

Bosch Dishwasher Drain Pump and hose

The motor /pump (pointed to in the picture above) was easy to remove.  I just needed to push the tab at the top, so I could rotate it out.

As I started to do so, water started flowing out, so I quickly put it back and found a pan to catch the water and continued removing the pump.

Once I got the drain pump out. I pulled up on the float to see if it turned on.

Nothing happened, and again, it seemed like it should.

Normally, I would pull out my multimeter and look at the voltage on the pump and see if pulling the float caused a voltage increase at the pumps terminals, which would indicate that yes, the pump motor is supposed to turn on.

But I guess I was lazy and I just assumed this was the problem. I searched for the Bosch Dishwasher Drain Pump online and found it was available on Amazon for only about $35.  So I ordered it.

Unfortunately it was Friday, so the part wouldn't come until the following week.

While waiting for the part, I concluded we could continue to use the dishwasher, but we'd have to manually empty the water from the bottom after each cycle.

We did that once and after pulling out soapy dishes, realized that since the water couldn't drain after the cleaning portion of the cycle, the rinse cycle was using dirty soapy water.

So we had to run the washer twice.  The first time with the soap to clean.  Then we (I) would manually drain the water and run the washer a second time, without soap, to rinse the dishes.

While it was a pain, we were still able to wash (and more importantly) sterilize our dishes (and baby bottles).

The pump arrived fairly quickly on the following Wednesday.  As soon as I got it, I excitedly tore apart the washer again and swapped it in.  I pulled the float, heard the relays click, and low and behold... the pump started spinning.

So I fixed the washer!

Or so I thought....

The washer worked for a few washes, but then a couple days later, there was standing water in the bottom again!

I was baffled.

I tore the machine apart and pulled it out, figuring there must be a clog in the drain pipe.

Bosch Dishwasher removed from cabinet showing drain pipe

In the picture above the drain pipe is the bottom of the two tubes on the side of the washer.  It runs from the drain pump in the front to the back.  You can see a little of the tube behind the washer which continues over under the sink and up to the "air gap" Y-connector before finally draining into the garbage disposal.

washer drain tubes under sink air gap y-connector

I was too lazy to pull all the tubes and check them, so I just removed pump again and the tube from the bottom of the air gap on the sink side and pored some water in it to see if the water would come out at the drain pump.

It did, so I decided there wasn't a clog in the drain tube.

I don't have a picture for all of that described above or the desire to explain it better, so do yourself a favor and remove the pieces of tubing and check the tubes for clogs.  Its pretty easy to do.

I put the washer back together and felt defeated.  I spent the next day mulling over where the problem could be and why it was intermittent.

The next day, I pulled the tube that goes from the y-connector air-gap to the garbage disposal, figuring that might be clogged.

It wasn't.

At that time I didn't understand the "air gap" piece and just figured it was a safety device as it has a hole in it for water to come out, if the garbage disposal was clogged and the water couldn't drain through it.

dishwasher air gap

I don't know why it took me so long to look up the purpose of the air gap (to keep bacteria from the garbage disposal from getting back into the dishwasher).  When I finally did, I found out that it easily gets clogged and you could remove the top piece of it to look to see if it was clogged.

air gap y-connector under sink
air gap y-connector removed
removing top from air gap y connector

Sure enough after doing so, I found the air gap, on the side of the dishwasher drain tube, was almost nearly clogged.

Clogged dishwasher air gap y-connector

In the picture above, that inner tube should be a hole all the way to the bottom, but it was nearly closed off with gunk.

So I cleaned the tube and put everything back together and everything has been working well ever since.

You can buy a new Y-Connector Air Gap for automatic dishwashers for just a few dollars.

In conclusion, I'm guessing the clogged y-connector caused the water to not be able to drain from the washer and therefore the pump to burn out.

I'm disappointed in my trouble shooting skills.  I should have checked that air gap as one of the first things I did.  I've noticed that lately I'm losing my logic... maybe its because we have a 14 month old (foster) baby that I swear gets stronger by sucking the life out of me.

37 comments on “Bosch Dishwasher Not Draining, Leaving Standing Water after the Wash Cycle Completes”

  1. Your entry was posted pat 4:37 a.m.!!! Did the 14 month old baby have anything to do with your being awake at that time? ๐Ÿ™‚

  2. Terry, I am having a problem with my dishwasher not draining and I came across this post...very helpful! More importantly to me is that I read that you have a 14 month old foster baby. I am a CASA for a foster child and have huge soft place in my heart for foster kids so that touched me very deeply. It takes a very special person to be a foster parent...thank you for being that person!!

    1. Hi Heidi... Thanks for your comment. I'm glad the article helped you!

      As an update... We've since adopted our foster child. We love him beyond belief.

      My wife does CASA as well. Along with currently getting her PHD, she also runs a 501c3 non-profit (www.FosterKinshkip.org) to help those that are raising their relatives kids.

      Finally, if you've got an extra $10 burning a hole in your pocket we are part of the Big Give donation drive where we are trying win the $4k Grand Prize for getting the most donations. We are hoping to get lots of small donations! You can donate here:

      Take care, and thanks again for taking the time to comment!

  3. I'd like to thank you for your post on "Bosch Dishwasher Not Draining, Leaving Standing Water after the Wash Cycle Completes". Using the information in your article I was able to get my dishwasher draining and running again without having to call a repair service. Thanks again!

  4. Terry, I have never responded or written to anyone on the internet but I feel compelled to write to you to let you know I read your entire article to my wife because I could have written it word for word myself based on my exact same experience. This includes tugging on the plastic valve in the washer and hearing it click, checking the tubes for obstructions, taking the whole thing apart, having the same cut finger as in your picture, considering the problem could be the air vent but then narrowing the problem down to the drain motor, ordering it on a Friday night because it was only $30 and having to wait for it, installing it when it finally arrived and thrilled when the part fixed the problem only to have the dishwasher stop again 2 weeks later which completely vexed me for the next few days. Then although I thought I had read everything on the internet about my problem including every Bosch manual and fix-it video, I was surprised to come across your comprehensive review with such a parallel story to my own. So I turned my attention back to the air gap after I previously consciously decided that couldn't be the problem. I tried to clean the one I had with pipe cleaners but after looking at your picture I was not convinced I could thoroughly clean it that way while it was installed. Then I remembered that I may have a new air gap tucked away in my garage which I quickly found no surprise to my wife. Although a bit tricky to remove due to the positioning of the old gap valve, I was able to get it out and replace it with the new one. We just ran a load of dishes and Voila! Perfect. Thank you so much! If you're ever in Los Angeles I want to buy you lunch.

    1. Ha! Thanks for responding with your story. Unbelievable how similar! And I'm glad you found my article and that it helped! Feedback like yours gives me drive to write more articles, so thanks again.

      I'll take you up on lunch someday! ...In the mean time... clicking on an ad always puts a few pennies in my virtual pocket ๐Ÿ™‚

  5. Terry - thanks for posting your story.
    I had a similar experience and replaced the drain motor without luck. I had thought that the hoses were clear, but after reading your tale I took off the air break and discovered the hose was mostly clogged.
    After a quick trip to Lowes to get a hose and air break the dishwasher now works like a charm.
    I kept the old motor around as a spare since it probably still works.


  6. This symptom started about a week ago, I took apart everything, cleaned everything, nothing worked. I was going crazy with this problem! I saw this post and checked the drain tube, and sure enough there was a big piece of plastic in there! It was one of the tabs that hold the silverware tray to the rack, which broke months ago. Took it out, and dishwasher worked great! Luckily my pump was still ok, cant imagine how much you saved me! Thanks man!

  7. Terry, I also need to add my gratitude for your post. I stumbled upon it and am so grateful. Our air intake was clogged as well. Luckily I found your post before tearing things apart.
    One more piece of appliance I fixed because of my dad's influence. You never know if you can fix it until you start fiddling,

  8. You're a life saver!!! ๐Ÿ™‚ i had exact same problem with mine.. thanks to you it's working ๐Ÿ™‚

  9. Thank you thank you thank you! I figured out my Bosch (with water in the tub) up to the float, but after I held my float up for about 15 seconds, the pump kicked on. We're running a wash now after findING no clogs. We shall see what happens and I'll post as soon as we see what happens. ๐Ÿ™‚

  10. Thank you! Two and half years later, your post is still relevant. I was having problems with my dishwasher not draining and this post helped me resolve it simply without costing me a plumber!

  11. What is the hose that comes up out of the water intake port? And where does the other end attach?? I have the same setup on my dishwasher

    1. Thanks for your question... unfortunately I don't understand what you are asking. I don't write about a "water intake port" in my article. Can you clarify your question a little further by further describing which hose are you asking about?

  12. Yes, sorry. The hose I'm referring to is the top long hose above the the drain hose. I looking at picture 7 from the bottom of your article. It is the picture that shows the left side of your dishwasher

      1. I see. Unfortunately we've since moved to a new house and I don't have this dishwasher anymore so I can't directly inspect it. I would assume its the line that feeds the water that goes into the dishwasher via the inner sprayers & rotating blades. I would say that, yes both ends should be attached to something... maybe the end that goes underneath feeds the bottom sprayers.

  13. Thanks for encouragement today 5/3/17 and your DW insides look like mine (SHS5AV56UC). Mine was not draining and the cycle just ended 2-4 min after starting. I pulled filter off along with the pump cover. My daughters small fingers felt something plastic and flat under drain pump turbine/paddle wheel (using light and mirror, this looks like a round white plastic that is connected to pump motor.) But couldn't get it over lip from below "turbine.". She had already pulled out the lemon seed.

    To float it out, I filled it with a few cups of water then lifted the float with power on. Started draining a little and then got the grinding sound. Well, I knew then the pump motor still worked! Red glass pieces visibly appeared near turbine hmmm, taped a drinking straw to shop vac hose and sucked the two pieces carefully raising out of turbine area sideways and up. (Didn't care about wet vac filter when DW is down!) Apparently, a broken red glass was pulled out of the rack a few weeks ago but no pieces were in tub area (no one told the handyman, me).

    After that, holding float up made pump cycle about 4 times then it stopped. I was surprised it didn't stay on constantly. I repeated that 3 times with no weird sounds. Put everything back and all was well. Don't forget pump cover. When cleaning filter in future, make sure to check for stuff down in filter hole before replacing with cleaned filter.

  14. Hey Terry. Thank you very much for your post. You're the only person I found with a post that begins to address my issue. My Bosch (SHE5AL02UC/05) is not draining and I have tried everything I can find on the web. I was so happy to see your post because you are the only person I saw refer to the overflow float. My situation is rather unique because when I pull the overflow (as you did) I hear the clicks that you refer to, but then the pump kicks in and the dishwasher drains. So I know I don't have any of the drainage issues caused by clogged hoses, but the pump still does not activate during the dishwasher cycles. I am guessing at this point that the pump wiring is shot because it is not coming on when activated. Any ideas before I order a new pump or call a plumber? Thanks!

    1. Hmmm... that's is an interesting situation. I'd need to see a wiring diagram to start to trouble shoot what's happening in your case. Based on what you are experiencing, it seems as though something is either wrong with the control board programming/logic or its connection to the motor.

      I'm guessing (again based on what you are experiencing) that the float connects the circuit for the drain motor power independently (likely in parallel) of the control board. In other words I'd bet that if the micro controller on the control board fried, that the float would still work the drain motor.

      I'm sorry I can't be more helpful in this case. You may want to try posting on a forum focused on repairs, if you can find a forum in the appliance repair realm.

      Sometimes there is a wiring diagram taped to the inside of the unit. On my current dishwasher (we moved since I posted this article) when I take of the front lower panel, the wiring diagram is taped inside. If you have one, take a picture and post and I'll see if I can help any further.

      1. Thank you so much for your response, Terry. You are truly awesome for sharing your knowledge and your time. I too think it is the control panel, as does the technician over at Appliance Parts Pros, so I ordered that and will install it to see what happens. Worst case scenario I will send it back for a full refund and order new pump - which is the only other thing it could be. Thanks again!

  15. Thanks Jeff,
    DW wasn't draining. Tried clearing out filters. Eventually tricked the door latch so it would run while open, allowing me to see that the drain pump impeller was in fact spinning.

    My problem ended up being a clogged air-gap, like yours. Had corn on the cob 'hair', a small chicken bone and a couple pumpkin seeds in there. I don't know how they could get past the screens and filters!

    So anyway, thanks for your blog. I've replaced DWs, swapped out motors, etc, but never realized that the air-gap had a removable inner cap.

  16. Glad I found your post! I did everything just as you did. Checked the lines, replaced the drain motor (twice, the first replacement was defective) and still had the issue. Iโ€™m going to the hardware store after work to purchase a new air gap. I hope thatโ€™s the culprit, if not it will be time for a new dishwasher as I am tired of dealing with it! Thanks!

  17. UPDATE: I removed the air gap and found a couple of whole peppercorns and a residue similar to butter inside. Since I had to crawl under the sink and remove it, I wasnโ€™t going to bother cleaning it. For ten bucks I replaced it with a new one. I have run the dishwasher twice now and it is draining properly (knock on wood). Noticeably, I can hear the water being pushed into the drain where it had become muted over the 20 or so years with the old air gap. Thanks again!

    PS- I felt like an idiot for not changing this first but at least I know Iโ€™m not the only one!

  18. Decided to post here as this webpage helped me 'repair' my Bosch machine in the same fashion as the author of this page. I, too, had an obstruction in the drain pipe that connects my main kitchen sink where the machine's drain pipe connects to . This obstruction caused a backup or pressure that prevented the Bosch from draining. I guess a pressure backup happened. Once I removed the obstruction, all was well and the Bosch dishwasher was happy again!

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