A Bosch dishwasher is a must-have, time-saving appliance. No matter how advanced the technology has become, it can easily fail, especially when we don’t give it the proper care and maintenance it deserves.
Drainage failure is a common problem you’ll encounter. In most cases, it can be solved and prevented by cleaning obstructions in different parts of the dishwasher.
If a component fails, you don’t necessarily have to replace your unit. Instead, you can replace the malfunctioning component to solve the issue.
We’ll delve into why your Bosch dishwasher isn’t draining and show you how to troubleshoot it.
Why isn’t my Bosch dishwasher draining?
A Bosch dishwasher that isn’t draining properly is most likely caused by an obstruction in the filter, drain pump, drain hose, or air gap.
If you don’t remove the knockout plug in a new garbage disposal, it will also cause drainage issues in the dishwasher.
Below, we’ve made a list of the most common causes of draining issues on a Bosch dishwasher. We also have step-by-step instructions to help you troubleshoot them.
| Causes | Solutions |
| Blocked Filter | • Unplug the dishwasher. Open the door, and remove the lower rack. • Locate the mesh filter at the bottom of the dishwasher. • Remove the bottom spray arm and set it aside. • Rotate the filter cap counterclockwise and lift the filter to remove it. • Remove any food residue and debris. Then, wash the filter in warm, soapy water. • Reinstall the filter. Rotate the filter cap clockwise until it is secure. • Reattach the bottom spray arm and the lower rack. • Close the door, and test if the dishwasher drains properly. |
| Obstructed Drain Pump | • Unplug the dishwasher. Open the door, and remove the lower rack. • Take off the bottom spray arm and set it aside. • Rotate the cap counterclockwise and lift the filter to remove it. • Use a sponge to soak up the water near the pump area. Wear protective gloves to prevent injuries. • Use a spoon to pry the pump cover. Then, hold the cover by the lug and pull it up. • Remove food residue and other foreign objects from the pump. • Reinstall the pump cover until it clicks. • Reattach the mesh filter, and rotate the cap clockwise to secure it. • Put the lower rack back and close the door. • Run a cleaning cycle to confirm that the dishwasher is draining. |
| Kinked or Clogged Drain Hose | • Unplug the dishwasher. • Check the drain hose for kinks and bent areas. • Place one end of the hose into a bucket. Straighten out any kinks and bent areas to promote better flow. • Inspect the hose for any blockages and remove any visible obstructions. • Use the drain function and let the water flow into the bucket. • Reconnect the drain hose and plug in the dishwasher. • Run a quick cycle to check if it drains. |
| Clogged Air Gap | • Locate the air gap and remove its stainless steel cover. • Pull out the inner cover to access the air gap. • Use a toothpick or bamboo skewers to pull out visible food particles and dirt from the air gap. • Get a shallow bowl and put it over the air gap. • Add towels around the air gap to absorb spills. • Start a brief rinse cycle to clear any remaining dirt and food residue. • Hold down the bowl to prevent water from spilling all over your counter. • Inspect the air gap again for any obstructions. Remove them if you find any. • Reattach the inner cover until it locks into place. Then, reinstall the stainless steel air gap cover. |
| Unremoved Knockout Plug | •Disconnect the drain hose, remove the garbage disposal, and set it on its side. • Use a hammer and screwdriver to knock out the plug. Then, remove the plug. • Reinstall the garbage disposal, and reconnect the drain hose. • Run a cycle to confirm that the drainage issue is resolved. |
| Loose Drain Pump Cover | • Unplug the dishwasher and turn off the water supply. • Open the door and remove the bottom rack. Take off the spray arm and set it aside. • Rotate the cap counterclockwise and lift the filter to remove it. Wear protective gloves to prevent potential injuries. • Check if the pump cover is installed correctly. If it is loose or missing, reinstall it. • Attach the pump cover until it clicks into place. • Reinstall the filter. Make sure the arrows align. • Return the spray arm and the bottom rack. • Turn on the water supply and plug in the dishwasher. Check if the drainage problem is resolved. |
| Drain Pump Failure | • Unplug the dishwasher and turn off the water supply. • Use a Torx 20 screwdriver to unthread the screws on the door. • Open the door and remove the mounting screws on the panel. • Close the door slightly and slide its outer panel down to remove it. Then, detach the control pad from the panel. • Unthread the screws on the access panel at the bottom of the dishwasher, and pull out the panel. • Remove the screws on the frame support. Use a flathead screwdriver to pull out the frame. • Take off the insulation to access the pump. • Locate the drain pump and unfasten the harness from its retaining clip. • Press the locking tab with a flathead screwdriver and simultaneously rotate the motor clockwise to unscrew it. • Disconnect the plug and remove the faulty drain pump. Wipe the water on the housing before installing the new pump. • Align the tabs on the new pump. Push it in and turn it counterclockwise to secure it. • Connect the plug and place the harness back into its retaining clip. • Reinstall the insulation and frame support. After, mount the access panel and secure it with its screws. • Reattach the control pad to the outer door panel. • Mount the outer door panel. Then, reinstall the screws on both sides of the door. • Turn the water supply on and plug in the dishwasher. Finally, check if the pump is working. |
Blocked Filter
A blocked filter is the most common culprit of a Bosch dishwasher’s draining problem.
Your filter traps food scraps, dirt, and debris, preventing them from soiling your dishes during wash cycles. It also protects the drain pump from large obstructions.
Cleaning the filter regularly is the best way to prevent draining issues. You can keep your dishwasher running in optimal condition wash after wash.
What you’ll need:
- Protective gloves
- Sponge
Solution: To clean your Bosch dishwasher filter, follow these steps:
- Step 1: Unplug the dishwasher and turn off the water supply.
- Step 2: Open the door and remove the racks.
- Step 3: Locate the mesh filter at the bottom of the dishwasher.
- Step 4: Take off the bottom spray arm and set it aside.
- Step 5: Rotate the filter cap counterclockwise and pull it out.
- Step 6: Pick up the food scraps and debris clogging the filter. Use protective gloves as glass shards may get stuck here.
- Step 7: Clean the filter in warm, soapy water.
- Step 8: Reinstall the filter and rotate the cap clockwise until it is secure.
- Step 9: Reattach the bottom spray arm.
- Step 10: Reinstall the racks and close the door.
- Step 11: Plug in the dishwasher and turn on the water supply.
- Step 12: Test if it drains properly.
Obstructed Drain Pump
Your dishwasher uses a pump to push drain water through a hose and into your home’s drain system. Located in the same area as the filter, the pump can also get clogged with grease, food scraps, broken glass, and other debris.
Once the pump is obstructed, your unit will either drain slowly or not drain at all. Like cleaning the filter, you have to remove the clog to promote better drainage.
What you’ll need:
- Protective gloves
- Sponge
Solution: To clean a clogged Bosch dishwasher drain pump, follow these steps:
- Step 1: Unplug the dishwasher and open the door.
- Step 2: Remove the bottom rack.
- Step 3: Remove the spray arm and set it aside.
- Step 4: Rotate the cap counterclockwise and lift the filter to remove it.
- Step 5: Use a sponge to soak up the water near the pump area.
- Step 6: Wear protective gloves to prevent potential injuries.
- Step 7: Use a spoon to pry the pump cover.
- Step 8: Hold the cover by the lug and pull it up.
- Step 9: Remove food scraps, dirt, and other debris from the pump.
- Step 10: Reinstall the pump cover until it clicks.
- Step 11: Reattach the mesh filter, and rotate the cap clockwise to secure it.
- Step 12: Put the lower rack back and close the door.
- Step 13: Plug in the dishwasher. Run a cleaning cycle to confirm that it is draining properly.
Kinked or Clogged Drain Hose
Kinks and bent areas in the drain hose can restrict water flow and cause clogs. You can just straighten kinked areas to promote better drainage, but obstructions have to be removed or flushed out of the house.
If you don’t scrape dishes properly before loading them into the dishwasher, they can block the hose and prevent water from flowing out during a drain cycle.
You’ll see dirty dishes and standing water inside the dishwasher if the hose is blocked. You might also hear unusual gurgling noises.
What you’ll need:
- Bucket
- Towels
Solution: To clean an obstructed drain hose on a Bosch dishwasher, follow these steps:
- Step 1: Unplug the dishwasher.
- Step 2: Check the drain hose for kinks and bent areas.
- Step 3: Place one end of the hose into a bucket. Straighten out any kinks and bent areas to promote better flow.
- Step 4: Inspect the hose for any blockages and remove any visible obstructions.
- Step 5: Use the drain function and let the water flow into the bucket.
- Step 6: Reconnect the drain hose and plug in the dishwasher.
- Step 7: Run a quick cycle to check if it drains.
Clogged Air Gap
An air gap is the small chrome or stainless steel fitting on your sink, which prevents dirty water from reentering your Bosch dishwasher. Tiny scraps of food and dirt can get trapped in this small area, causing drainage problems among other issues.
If the air gap is clogged, you might notice dirty water leaking from it, as well as unpleasant smells. You can easily clean the obstruction by pulling it out or flushing it out with water.
What you’ll need:
- Toothpick/bamboo skewers
- Shallow bowl
- Towels
Solution: To clean a clogged air gap, follow these steps:
- Step 1: Locate the air gap and remove its stainless steel cover.
- Step 2: Pull out the inner cover to access the air gap.
- Step 3: Use a toothpick or bamboo skewers to pull out visible food particles and dirt from the air gap.
- Step 4: Get a shallow bowl and put it over the air gap so that water will flow into the sink instead of the counter. Add towels around the air gap to absorb spills.
- Step 5: Run a brief rinse cycle to clear any remaining dirt and food residue.
- Step 6: Wait for the water to flow out of the air gap. Hold down the bowl to prevent water from spilling all over your counter.
- Step 7: Inspect the air gap again for any obstructions. Remove them if you find any.
- Step 8: Reattach the inner cover until it locks into place.
- Step 9: Reinstall the stainless steel air gap cover.
| Quick Note: • Not all dishwashers are connected to an air gap. If yours isn’t, you can rule this one out and look for the clog elsewhere. |
Unremoved Knockout Plug
If you have a newly installed garbage disposal system, you’ll find a knockout plug inside the inlet where the dishwasher hose connects. Since not all households have a dishwasher, this area is typically blocked by a plug to prevent leaks.
Not to worry, you can easily knock out the plug—as its name suggests. All you need is a hammer and a screwdriver to push the plug and remove it from your garbage disposal.
What you’ll need:
- Hammer
- Screwdriver
Solution: To remove a garbage disposal knockout plug, follow these steps:
- Step 1: Unplug the garbage disposal, and disconnect the drain hose.
- Step 2: Remove the garbage disposal and set it on its side.
- Step 3: Use a hammer and screwdriver to knock out the plug.
- Step 4: Remove the plug.
- Step 5: Reinstall the garbage disposal.
- Step 6: Reconnect the drain hose.
- Step 7: Run a cycle to confirm that the drain error is resolved.
Loose Drain Pump Cover
If you don’t install the drain pump cover properly after cleaning it, you might get an E24 drain error on your Bosch dishwasher.
Whether loose or missing, an incorrectly installed cover will put a lot of stress on the pump. To protect the pump from damage, your dishwasher might stop draining until you reinstall the cover properly, which should only take about 5 minutes or less.
What you’ll need:
- Hammer
- Screwdriver
Solution: To reinstall a loose or missing drain pump cover on a Bosch dishwasher, follow these steps:
- Step 1: Unplug the dishwasher and turn off the water supply.
- Step 2: Open the door and remove the bottom rack.
- Step 3: Remove the spray arm and set it aside.
- Step 4: Rotate the cap counterclockwise and lift the filter to remove it.
- Step 5: Wear protective gloves to prevent potential injuries.
- Step 6: Check if the pump cover is missing or loose. Reinstall it if necessary.
- Step 7: Pry the pump cover using a spoon and pull it out of the dishwasher.
- Step 8: Attach the pump cover until it clicks into place.
- Step 9: Reinstall the filter. Make sure the arrows align to secure it.
- Step 10: Return the spray arm and the bottom rack.
- Step 11: Turn on the water supply and plug in the dishwasher.
- Step 12: Check if the E25 error is resolved.
Drain Pump Failure
If the drain pump has no clog but isn’t pumping water out of the dishwasher, it most likely isn’t functioning properly. A continuity check will help you confirm that the component is faulty.
An E25 error code will also appear on the display, indicating a drain pump error. Once it is defective, you can no longer repair it, but you can always replace it.
Although the fix isn’t easy, you can perform it yourself with a few tools and our step-by-step guide.
What you’ll need:
- Towel
- Phillips screwdriver
- Flathead screwdriver
- Torx 20 screwdriver
- Multimeter
- New drain pump
Solution: First, perform a continuity test to confirm that the drain pump is faulty. If it has no continuity, replace the pump to fix the drain problem.
- Step 1: Unplug the dishwasher and turn off the water supply.
- Step 2: Use a Torx 20 screwdriver to unthread the screws on the door.
- Step 3: Open the door and remove the rest of the screws on the panel.
- Step 4: Close the door slightly and slide its outer panel down to remove it.
- Step 5: Disconnect the control pad from the outer door panel.
- Step 6: Unthread the screws on the access panel at the bottom of the dishwasher. Then, remove the access panel.
- Step 7: Remove the screws on the frame support.
- Step 8: Use a flathead screwdriver to pull out the frame.
- Step 9: Remove the insulation to access the pump.
- Step 10: Unfasten the harness from its retaining clip.
- Step 11: Press the locking tab with a flathead screwdriver and rotate the motor clockwise to unscrew it.
- Step 12: Disconnect the plug and remove the drain pump.
- Step 13: Set your digital multimeter to the lowest settings for ohms of resistance or resistance with tone.
- Step 14: Place the black meter lead to one of the terminals on the drain pump and the red lead to another terminal.
- Step 15: Check the reading on the multimeter.
A functioning drain pump will show 15 to 40 ohms of resistance. If there’s little to no change on the multimeter display, the pump has no continuity and needs a replacement.
To replace a faulty drain pump on a Bosch dishwasher, follow these steps:
- Step 1: Unplug the dishwasher and turn off the water supply.
- Step 2: Use a Torx 20 screwdriver to unthread the screws on the door.
- Step 3: Open the door and remove the screws on the other side of the door.
- Step 4: Close the door slightly and slide its outer panel down to remove it.
- Step 5: Detach the control pad from the outer door panel.
- Step 6: Unthread the screws on the access panel at the bottom of the dishwasher. Then, remove the access panel.
- Step 7: Remove the screws on the frame support.
- Step 8: Use a flathead screwdriver to pull out the frame.
- Step 9: Remove the insulation to access the pump.
- Step 10: Unfasten the harness from its retaining clip.
- Step 11: Press the locking tab with a flathead screwdriver and simultaneously rotate the motor clockwise to unscrew it.
- Step 12: Disconnect the plug and remove the faulty drain pump.
- Step 13: Wipe the water on the housing before installing the new pump.
- Step 14: Align the tabs on the new pump. Push it in and turn it counterclockwise to secure it.
- Step 15: Connect the plug and place the harness back into its retaining clip.
- Step 16: Reinstall the insulation and frame support.
- Step 17: Mount the access panel and secure it with its screws.
- Step 18: Reattach the control pad to the outer door panel.
- Step 19: Mount the outer door panel. Then, reinstall the screws on both sides of the door.
- Step 20: Turn the water supply on and plug in the dishwasher.
- Step 21: Check if the pump is working.
Tips for Preventing Future Drainage Issues on a Bosch Dishwasher
Here are a few tips to avoid drainage issues on a Bosch dishwasher.
- Run a hot cycle to clean the dishwasher.
- Clean the filter and pump regularly.
- Straighten kinks and bent areas on the drain hose.
- Scrape food scraps off your dishes.
Run a hot cycle to clean the dishwasher.
Prevent greasy food residues from accumulating in your dishwasher by running the hottest and longest cycle a few times per year. Just add a single Bosch dishwasher cleaner to an empty tub when you run the cycle.
Additionally, you must descale your dishwasher regularly, especially if you reside in a hard water area. It will keep your unit running smoothly and prevent expensive repairs.
Use the Bosch descaler a few times per year to remove limescale buildup and hard water deposits. Run the hottest and longest wash cycle on an empty load and without detergent.
Add a box of descaler at the bottom of the dishwasher after 30 minutes, and let the wash cycle continue. Once done, run a second wash cycle to clean your dishwasher.
Clean the filter and pump regularly.
Clean the filter every 3 to 6 months, depending on your usage. If your household uses hard tap water, you must clean the filter monthly to prevent hard water deposits from blocking it.
Since the pump and the filter are located in the same area, you might as well clean the pump whenever you clean the filter. Make sure to use protective gloves to protect your hands from potential injuries.
Straighten kinks and bent areas on the drain hose.
Inspect the drain hose for kinks and bent areas. Straightening them out will improve the flow of water and prevent drainage issues.
At the same time, it can prevent permanent damage to the drain hose. If you see signs of damage like rips and holes, the hose must be replaced to prevent water leakages and other issues.
Scrape food scraps off your dishes.
Prevent large chunks of food from causing clogs in your dishwasher by scraping your dishes before loading them onto the appropriate racks. This should help minimize the occurrence of obstructions in your dishwasher.
Contrary to popular belief, you don’t have to pre-rinse or pre-wash your dishes before popping them into the dishwasher.
Frequently Asked Questions
On most Bosch dishwashers, the Start button doubles as a Reset button. Just press and hold this button for three seconds until you see the display resetting.
Depending on your model, you might have to press a different button like the Cancel or Drain button. We recommend checking your user manual for more detailed instructions for resetting your unit.
If your Bosch dishwasher isn’t draining and has standing water at the bottom, you must manually clean it up and resolve the underlying issue to fix the drainage problem. You can use a sponge to soak up the water inside the dishwasher.
Once clear, you can clean the filter and pump to improve the flow of water and promote better draining. If none of those fixes resolve the problem, there might be a clog elsewhere, which requires cleaning.
A continuity test will help determine if your Bosch dishwasher is functioning properly. You need a multimeter to perform it.
Turn the dial on a digital multimeter to the lowest settings for ohms of resistance or resistance with tone. Touch the black meter lead to one of the terminals on the drain pump and the red lead to another terminal.
A drain pump with continuity will have 15 to 40 ohms of resistance. Little to no change indicates a lack of continuity, which means it is malfunctioning and requires replacement.
