If you’ve opened your Bosch dishwasher after a cycle and found standing water at the bottom or dishes that are still dirty and wet, you’re not alone. A Bosch dishwasher not draining properly is one of the most common issues owners face, and it can be frustrating when it seems like everything else is working fine.

In many cases, the problem comes down to simple causes like a clogged filter or a kinked drain hose. This guide covers why your Bosch dishwasher may not be draining completely, provides quick steps to fix it even when there’s no obvious blockage, and explains when it’s time to call in a professional.

Why Is My Bosch Dishwasher Not Draining?

A Bosch dishwasher not draining water can usually be traced back to a handful of common issues. Even when there’s no visible blockage, internal components can still cause problems. Here’s a breakdown of what might be going wrong inside your unit.

Clogged or Dirty Filter

The filter sits at the bottom of your Bosch dishwasher, usually under the lower spray arm. Its job is to trap food particles and prevent them from clogging the drain system. Over time, the filter can get packed with debris, which stops water from draining completely. To clean it, twist and remove the filter assembly, then rinse it under warm water and scrub it gently with a soft brush to remove any buildup.

Blocked Drain Hose

The drain hose carries wastewater from the dishwasher to the sink drain or garbage disposal. If it’s kinked, crushed, or clogged with gunk, water won’t drain properly. This is a common reason why your dishwasher is not draining completely, especially if the unit was recently moved or installed.

Faulty Drain Pump

If the filter and hose are clear but the water still isn’t going anywhere, the drain pump might be the issue. You’ll usually hear a low humming sound without water movement, or nothing at all. This pump forces water out of the dishwasher, and if it’s burned out or jammed with debris, you’ll need to repair or replace it to get things working again.

Stuck or Broken Check Valve

The check valve prevents dirty water from flowing back into the dishwasher. When it’s stuck or broken, water can stay in the tub even after a cycle. This can make it appear that your Bosch dishwasher is not draining, even when everything else is functioning properly.

Air Gap or Garbage Disposal Issues

If your setup includes an air gap, usually a small cylinder near the faucet, it can become clogged with grease or food particles. Similarly, a full or jammed garbage disposal can block the dishwasher’s drain path. Clearing either can quickly resolve the problem with your Bosch dishwasher not draining.

Knockout Plug Still in Garbage Disposal

When installing a new garbage disposal, there’s a plastic knockout plug inside the dishwasher drain port that must be removed. If it’s left in place, water won’t be able to exit the dishwasher. This issue is often overlooked during new installations and is a common reason for a Bosch dishwasher not draining, but no blockage is visibly present.

Quick Fixes for a Bosch Dishwasher Not Draining

In many cases, you don’t need to dig too deep to get your Bosch dishwasher draining again. These quick fixes often resolve the issue without requiring a service call.

Run Your Garbage Disposal First

If your dishwasher drains through the garbage disposal, food buildup inside can block the flow of water. Run the disposal for 15–30 seconds to clear any clogs. It’s a simple step that often solves the issue in minutes.

Clean the Filter and Pump Area

Even if you’ve cleaned the filter before, the area around it can trap debris and grease.

Steps to clean it safely:

• Turn off the dishwasher and unplug it (or shut off the breaker).
• Remove the lower rack and locate the filter unit at the bottom.
• Twist and lift out the filter assembly.
• Rinse under warm water and scrub with a soft brush.
• Use a sponge or cloth to wipe out any debris in the sump area.
• If you see a pump cover, carefully remove it and check for clogs.
• Avoid sharp objects, as some debris may be broken glass or hard food.

Check and Straighten the Drain Hose

Look behind the dishwasher or under the sink to find the drain hose. Make sure it’s not pinched, bent, or collapsed. If needed, disconnect it and flush it with water to clear any hidden buildup. A blocked or kinked hose is a common reason your Bosch dishwasher water is not draining properly.

Reset Your Bosch Dishwasher

Sometimes, a simple reset can clear minor errors or glitches in the control panel.

How to reset most Bosch dishwashers:

• Open the door just enough to see the control panel.
• Hold down the Reset or Start button for around 4 seconds.
• The unit will automatically pump out any remaining water, which takes about a minute.
• Once finished, the current cycle will be canceled. Open the door fully and press the On/Off button to complete the reset.

Advanced Troubleshooting (If Basic Fixes Don’t Work)

If your Bosch dishwasher is still not draining after trying the quick fixes, it’s time to dig a little deeper. These advanced checks can help you spot issues that aren’t immediately obvious.

Inspect the Drain Pump for Damage

The drain pump plays a critical role in pushing water out of the dishwasher. When it fails, draining stops altogether.

Signs your pump may be failing:

• A humming sound with no draining action
• Water remaining in the bottom after the cycle
• Unusual noises during draining
• No sound at all when the drain cycle starts

Test the Check Valve

To test the check valve, remove the drain hose from the back of the unit and gently flush water through it in the reverse direction. If water can’t pass through, the valve may be stuck closed. If it’s loose or doesn’t seal properly, it may be letting water back into the tub. Either case means it’s time for a replacement.

Is Your Dishwasher Level?

If your Bosch dishwasher isn’t sitting evenly, water may not flow toward the drain correctly. Use a level to check side-to-side and front-to-back positioning. Adjust the leveling feet as needed to ensure water flows properly during the cycle. It’s a simple fix that’s often overlooked.

Electronic Control Board Issues

Though less common, a failing electronic control board can prevent your dishwasher from draining properly. This internal component controls the pump and drainage cycle. If the dishwasher isn’t responding to commands, displays error codes like E24 or E25, or skips parts of the cycle, it may be an issue with the control board. This type of repair is best handled by a qualified technician.

How to Prevent Your Bosch Dishwasher from Not Draining Again

Once you’ve solved the draining issue, the best move is making sure it doesn’t happen again. A few small habits can go a long way.

Regularly Clean Filter and Spray Arms

Food particles and grease can build up quickly. Cleaning the filter once a week and checking the spray arms for clogs helps ensure that water flows and drains properly.

Scrape (Don’t Rinse) Plates Before Loading

Rinsing can actually trick your dishwasher’s sensors. Just scrape off leftover food into the trash and load your dishes. It helps prevent clogs while allowing the dishwasher to function efficiently.

Run Hot Water Before Starting the Dishwasher

Before starting a load, run the kitchen faucet until the water reaches a hot temperature. This helps the dishwasher start with hot water immediately, improving cleaning performance and reducing the chances of greasy buildup in the drain path.

Monthly Dishwasher Maintenance Tips

Keeping your Bosch dishwasher running smoothly doesn’t require much effort. Just set a reminder to do these monthly:

• Run an empty cycle with a dishwasher cleaner or white vinegar
• Wipe down the door seal and edges to prevent mold
• Check for buildup in the filter and drain area
• Inspect the drain hose for bends or early signs of wear

When to Call a Bosch Appliance Repair Professional

If your Bosch dishwasher is still holding water despite your best efforts, it may be time to bring in a pro. Issues like a failed drain pump, control board malfunction, or broken internal components often require tools and knowledge that go beyond DIY.

Look out for signs like frequent error codes, power issues, or repeated draining failures after resets. Factory-trained technicians understand Bosch systems inside and out, ensuring repairs are done right the first time. While costs can vary, hiring a professional can save you time, prevent bigger problems down the road, and protect your investment in a high-end appliance.

Frequently Asked Questions

Why is there standing water in my Bosch dishwasher?

It’s usually caused by a clogged filter, blocked hose, or a drain pump issue.

How do I unclog the drain on my Bosch dishwasher?

Clean the filter, check the drain hose, and run the garbage disposal to clear any blockages.

Should there be water in the bottom of the dishwasher after a cycle?

A small amount is normal, but standing water means there’s likely a drainage problem.

Can a Bosch dishwasher drain pump be repaired or replaced?

Yes, depending on the issue, the drain pump can be cleaned, repaired, or fully replaced.

What does the Bosch error code E24 or E25 mean?

These codes indicate a drainage problem, typically caused by a clogged filter or pump.

Need Help With a Bosch Dishwasher That Won’t Drain? We’re Here.

If you’ve tried the fixes above and your Bosch dishwasher still won’t drain, it might be time for a professional repair. Give Wilshire’s factory-trained appliance techs a call at (818) 898-9999! We offer same-day or next-day service to get your dishwasher back in action quickly.