Bosch Dishwasher Not Draining

If you have a problem with your Bosch dishwasher not draining then the good news is that, in most cases, this type of fault is simple to fix and is a repair that you can undertake yourself.

Sometimes a dishwasher not draining is a symptom of a more serious issue that will require a replacement part or professional repair, but you should always begin by trying some basic troubleshooting which will hopefully help you diagnose where exactly the problem lies.

The most common reason for your Bosch dishwasher failing to drain is a blockage, so the first step is to check the filter for any food debris causing an obstruction. With the dishwasher powered off remove the bottom dish rack to give yourself better access to the basin of the dishwasher. It’s not the most pleasant job if the tub is still full of dirty water, but the filter tube should still be easily visible and can be removed with an anticlockwise twist.

Once removed it’ll be obvious if the filter is cause of the blockage as it’ll be clogged up with food debris and the dishwasher should begin to drain once it has been removed. If it is indeed the culprit then simply removed the debris and give the filter a good wash and rinse. If your Bosch dishwasher is still not draining then you’ll need to continue downwards into the basin and towards the drain pump.

After the filter is removed you’ll be faced with a drain mesh which simply lifts out. At this point you’re going to need to remove as much water as possible from the dishwasher to allow you to examine the drain pump. A wet dry vacuum is the ideal tool for this job but if you haven’t got one to hand then you’ll have to make do with scooping out as much as you can then and using kitchen towels to soak up the remaining water sitting down in the sump.

At this point it’s worth reminding you to double check that the dishwasher power supply is definitely turned OFF. Once you’ve shifted the water it’s time to remove the drain pump cover, which on most Bosch dishwashers will be secured with a single screw. Remove that using a screwdriver and then take off the cover by gripping the tab on the left and lifting it up and towards you.

With the cover removed you now have access to dishwasher drain pump. On top of the pump are impeller blades which are used to force the water out of the basin and into the pump. Just like you did with the filter, check for and bits of food debris which could be preventing the water from draining.

Even if there aren’t any large bits of food/waste which could be causing an obvious obstruction it’s still worth removing any visible debris and making sure everything is nice and clean as there shouldn’t really be anything getting below the filter and down to the drain pump at all.

With everything cleaned up it’s reassembly time! Replace the drain pump cover, then the drainage mesh, then the filter, and finally the lower dish rack. Now run your dishwasher on it’s shortest cycle to check if you’ve managed to fix the problem.

Other Causes

If you’ve followed the steps above to clear any blockages in the basin and your Bosch dishwasher still isn’t draining then are a few other faults that could be causing the issue –

  • There could be a blockage somewhere else. Check the dishwasher waste pipe for obstructions. It’s unlikely any large pieces of food debris have found there way through both the filter and the drain pump, but grease and fat can get through whilst hot and then turn solid as they cool down. Try squeezing the waste pipe along it’s length to break it up, then run on the dishwasher on it’s hottest cycle to shift any remnants.
  • The drain pump itself could have failed, in which case it will need replacing. Fortunately they are not very expensive although you might want to consider paying for a professional to do the job if you aren’t confident doing repair work yourself.