Bosch Dishwasher Not Draining (Solved!)5 min read

The Bosch brand is known for its well-made, reliable dishwashers. However, sometimes Bosch owners run into an issue where the dishwasher fails to drain properly, and water starts to pool at the bottom of the appliance. So, if this drainage issue happens to your Bosch dishwasher, what should you do to fix it?

If your Bosch Dishwasher isn’t draining properly, first, try removing and cleaning the filter at the bottom of the dishwasher. Then, consider if your garbage disposal, air trap, and/or drain hose could be clogged. If you have a clog or can’t find the issue, it’s time to call a plumber.

Before you start searching for a repairperson to save the day, let’s take a closer look at some of the most common issues and solutions for a Bosch dishwasher not draining properly. That way, you can hopefully save yourself the hassle (and cost) of getting professional assistance.

Why Did My Bosch Dishwasher Stop Draining? 3 common reasons

There are a couple of different things that could prevent a Bosch dishwasher from being able to drain water properly. The most common issues that can cause this are a failure with the drain pump, a clogged filter, and a clogged air gap.

Let’s go through each of these causes so that you can see why they might block your Bosch dishwasher from draining water.

Drain Pump Failure

The drain pump is part of a Bosch dishwasher that’s responsible for forcing water to flow through the drain hose. So, if water isn’t draining from your dishwasher, you can surmise that some sort of failure has occurred with your drain pump.

Typically, this is due to something getting caught in it, such as food from dirty dishes or other miscellaneous debris.

Dishwasher Drainage Pump
I’ve removed my dishwasher drain pump but don’t worry, our fixes below don’t require that you do this.

Clogged Filter

A clogged filter is another common occurrence that could prevent your Bosch dishwasher from draining water.

When your dishwasher is full of water, the water drains out through a filter to make sure that none of your smaller dishes or silverware go down the drain. If this filter gets clogged up, then the water won’t have anywhere to go — and it’ll begin to pool up at the bottom of your dishwasher instead.

Bosch Dishwasher Filter
This picture was taken after I cleaned my filter – yours may look a lot dirtier than this initially!

Clogged Air Gap

The first thing to mention here is that not all models of Bosch dishwashers even have an air gap. However, there are some models that do, and a clogged one could lead to issues with drainage.

The dishwasher air gap is a device that serves to keep dirty water from flowing back into the dishwasher. When your dishwasher is running, the air gap leads the wastewater away from the dishwasher and into a drainage site.

Sometimes, this part can get clogged up with food or debris. If this happens, your wastewater won’t have anywhere to go, and it’ll simply pool up at the bottom of your dishwasher. If you think this is the case, read our other article on how to fix a leaking air gap.

Dishwasher Air Gap
You’ll know if you have a dishwasher air gap if one of these devices is on your sink.

How Do I Fix the Issue?

Now that you have a general idea of what the problem could be, you’re ready to try and fix it. Let’s go through a couple of solutions to fix the problems that we discussed above.

Remove the Filter and Clear Debris

Something a lot of Bosch dishwasher owners don’t know is that the filter on the inside of the dishwasher is supposed to be checked and cleaned regularly. Thankfully, this means it’s also removable.

Let’s quickly go through the steps for removing and cleaning your dishwasher filter:

  1. Remove the dishwasher rack by pulling it up from the rails at the bottom.
  2. Unlock the filter unit located at the base of the dishwasher and pull it out.
  3. Remove the cylindrical filter from the filter unit by unscrewing it.
  4. Clean both parts of the filter unit by running them under water. If you need to scrape something off of the filter, use a small brush to gently scrape. Doing anything more could potentially damage the filter unit.
  5. Put the filter unit back together and place it back in your dishwasher.

Once you’re done, try running your dishwasher. If it fills with water and then drains normally, then problem solved! However, if it still doesn’t drain water, then your issue probably wasn’t a blocked filter.

Check the Garbage Disposal

The drain hose from a Bosch dishwasher typically leads directly into the garbage disposal drain. That means that if there’s food or other debris blocking up your garbage disposal, then your Bosch dishwasher won’t have anywhere to send the water, leaving it to pool up at the bottom of your dishwasher.

To fix this, all you have to do is run your garbage disposal to clear out any food. A great way to ensure that nothing is in the garbage disposal is to turn on the water above your garbage disposal and run the garbage disposal for about 15 seconds. This basically guarantees that anything in your garbage disposal will be disposed of.

After you’ve done this, run your dishwasher with nothing in it and see if the water has drained afterwards. If it has, then you’re all set. However, if it hasn’t, then a clogged garbage disposal also wasn’t likely the source of your issues.

Clear Your Air Gap

Clearing your Bosch dishwasher’s air gap isn’t something a lot of people think to do when their dishwasher stops draining, but it could potentially fix the issue.

Once again, it’s worth mentioning that not all models of Bosch dishwashers even have an air gap. If yours has one, it will look like a cylinder fitting that sits next to the sink that your dishwasher is connected to.

Water draining from your dishwasher flows through this cylinder fitting, so a clog in it will also prevent water from draining from your dishwasher.

If your Bosch dishwasher has an air gap, you can clean it by removing the cover at the top of the cylinder and wiping away any debris you see with a paper towel. Once you’re done, run your dishwasher with nothing in it and see if the water has drained afterwards.

If it hasn’t, then the air gap unfortunately wasn’t the cause of your problem.

See if the Drain Hose is Obstructed

The drain hose is the hose that connects this whole system we’ve been describing so far. Once waste water passes through the filter and the drain pump, it enters the drain hose and is carried through the air gap and garbage disposal into the disposal drain.

The problem here is that sometimes the Bosch dishwater drain hose becomes obstructed. This can of course be due to food and other debris, but it could also be simple kink like you would find with any other kind of hose. If that’s the case, you just need to straighten out your drain hose.

Most of the time, water being unable to flow through a drain hose is due to a clog in the hose. All you have to do to fix a clogged drain hose is follow these steps:

  1. Turn off your dishwasher and its water supply to make sure there’s no water or power in the system while you’re working.
  2. Next, unclamp your dishwasher’s drain hose from either the sink drain or the garbage disposal.
  3. Use something narrow and long (such as a straightened wire hanger) to remove any visible clogs in the drain hose.
  4. If you can’t reach a clog, try disconnecting the hose entirely and running water through it.
  5. Once all clogs are gone, reattach your drain hose to your dishwasher.

Once you’ve done this, try running your dishwasher with nothing in it and see if the water has drained afterwards. If it doesn’t, then the drain hose likely wasn’t the culprit in this case.

When to Call a Professional

There are, of course, other issues beyond the ones we’ve covered that could lead to a Bosch dishwasher not running properly. However, the ones we’ve discussed are the ones that are simple enough to fix on your own.

So, what should you do if none of our solutions fixed your problem?

The answer here is a simple one, but it’s probably not your favorite one to hear. At this point, all you can do is call a professional to help find the problem with and fix your Bosch dishwasher.

The solutions from here on out will likely involve tinkering with the actual mechanics of the dishwasher, so to prevent any damage to the machine, it’s best to just let a professional handle the situation.

+ posts

Hi, I'm Ed, and I run BuildFanatic! I enjoy providing the best possible information on a range of home improvement topics.

Leave a Comment

Your email address will not be published. Required fields are marked *