Fixing Bosch Dishwasher Draining Issues

Bosch Dishwasher that will not Drain

Picture of Bosch Dishwasher that won't drain
Picture of Bosch Dishwasher that won't drain

Dishwasher Not Draining

After our Bosch dishwasher ran a washing cycle, the bottom of the dishwasher was still full of dirty water. There is a pump in the dishwasher that pumps the water out of the dishwasher through the drain hose. The drain hose typically runs from the dishwasher to the sink or the air gap. Our dishwasher has the air gap that fits the top of the sink. From there, another hose connects to the split in the air gap and connects to the garbage disposal.

Check the Filter inside the Dishwasher Before Checking the Air Gap or Detaching the Drain Hose

To troubleshoot the problem, I first checked the filter in the dishwasher looking for something that could be blocking the flow of water. There is a screen in the dishwasher that is supposed to block large items from going into the drain hose, but sometimes, small pieces of food can get through and clog the hose.

If you find a big piece of food or glass caught in the filter, remove it and then run the rinse cycle to see if the dishwasher drains. If the dishwasher still doesn't drain, move to the next step.

Air Gap on Sink

Air gap with cover removed
Air gap with cover removed

Air Gap with Plastic Top Removed

Top of Air Gap Removed to check for bits of food
Top of Air Gap Removed to check for bits of food

Check the Air Gap for Clogs

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

  1. Remove the air gap cover. Most just unscrew or pop off by hand, but some have a small screw that holds it in place.
  2. 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 clogging the air gap.

Water is pumped from the dishwasher up through the air gap (That's the built-in plastic tube) and then usually through a larger hose to the garbage disposal. As the water hits the top of the air gap small bits of food get stuck between the plastic lid and the built-in tube. That prevents the hose from working efficiently so the dishwasher doesn't completely drain. It's amazing that this problem is typically caused by tiny bits of food.

If pieces are found to have clogged the air gap and removed, 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.

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

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.

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Comments 32 comments

gredmondson profile image

gredmondson 6 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.

LillyGrillzit profile image

LillyGrillzit 6 years ago from The River Valley, Arkansas

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

Hello, hello, profile image

Hello, hello, 6 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.

Psalmist4M profile image

Psalmist4M 6 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.

ethel smith profile image

ethel smith 6 years ago from Kingston-Upon-Hull

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

2patricias profile image

2patricias 6 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.

abrarr profile image

abrarr 6 years ago from USA

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

Drax profile image

Drax 6 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... ;-)

Paradise7 profile image

Paradise7 6 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.

John B Badd profile image

John B Badd 6 years ago from Saint Louis, MO

These are some great tips.

GojiJuiceGoodness profile image

GojiJuiceGoodness 6 years ago from Roanoke, Virginia

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

sheila b. profile image

sheila b. 6 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!

br14nwll 5 years ago

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

plumbing 5 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.

Dave P 5 years ago

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

DM 5 years ago

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

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!

darlenebb 4 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.

jdh 4 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.

Davidrwells 4 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.

Paul Edmondson profile image

Paul Edmondson 4 years ago from Burlingame, CA Author

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

Celine 2 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.

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.

Jennifer 2 years ago

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

Jodi 7 months ago

it worked!!! thanks a million!

Ash 3 months ago

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

Krista 2 months ago

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

Paul Edmondson profile image

Paul Edmondson 2 months ago from Burlingame, CA Author

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

Kristina 7 weeks 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

Paul Edmondson 6 weeks ago from Burlingame, CA Author

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.

Jesse S 6 weeks 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

Paul Edmondson 6 weeks ago from Burlingame, CA Author

Jesse, I'm glad it worked well!

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