How to Troubleshoot a Bosch Dishwasher Not Draining Water

Dishwasher draining problems are one of the most common issues for this hardworking appliance. Why won’t my Bosch dishwasher drain water? A clogged filter may be restricting water flow. Determine the most likely reasons for a Bosch dishwasher not draining water with these troubleshooting tips.

Why Is My Bosch Dishwasher Not Draining Like it Should?

Is there supposed to be water in the bottom of the dishwasher? Normal draining functions shouldn’t leave any water behind. Here’s how to pinpoint what’s causing that puddle when you find your Bosch dishwasher not draining.

Obstructed Dishwasher Drain Hose

A dishwasher’s drain hose connects to the sink or disposal, allowing water to exit at the end of a wash cycle. If the hose is kinked, water flow can be restricted and back up into the dishwasher. Though some kinks can be straightened to restore water flow, the hose should be replaced if the kink caused damage. 

Drain hose blockages are also possible when your Bosch dishwasher won’t drain water. These blockages often occur from accumulated debris or a large food particle that can be prevented with the right dishwasher loading tips. Though obstructions can be removed by disconnecting the hose, this complex job is best reserved for an experienced DIYer or professional repair service.

Follow these guidelines to remove a Bosch dishwasher drain hose obstruction:

1. Turn off the dishwasher’s power and water supply.
2. Unclamp the drain hose from the sink drain or disposal.
3. Remove any visible clogs with a straightened wire hanger or pliers.
4. If no clogs are visible, the hose must be disconnected at the dishwasher.
5. A clog or obstruction that can’t be reached means the hose must be replaced.

Dishwasher Filter Requires Cleaning

A clogged filter is one of the most common causes for a Bosch dishwasher not draining water. The filter screens out food particles and debris to prevent them from clogging the drain pump. However, if the filter becomes clogged, water won’t be able to pass through the filter and will remain in the wash tub. If your dishwasher isn’t cleaning dishes thoroughly or smells of mold or mildew, the filter may be due for a cleaning.

Here’s how to clean a Bosch dishwasher filter:

1. Remove the dishwasher’s bottom rack.
2. Rotate the filter knob to the left and lift up to remove.
3. Remove the filter from the mesh screen and rinse both separately under running water.
4. To remove lingering debris, scrub the filter and screen with dish detergent and a soft brush.
5. Dry both components and reassemble.
6. Replace the filters and rotate the knob to the right to secure.

Dishwasher Drain Pump Failure

A dishwasher drain pump uses a motor and impellers to expel water from the dishwasher tub and into the drain hose. If the impellers break or the pump motor fails, water will remain in the tub at the end of a wash cycle.

Before inspecting the pump, any standing water must be removed. Wondering how to drain a dishwasher with standing water? Scoop up as much as possible with a cup or bowl before absorbing the remainder with towels. If the impellers are damaged or the motor shows no continuity with multimeter testing, the pump requires replacement by a dishwasher repair service.

Check Air Gap and Garbage Disposal

The final step in Bosch dishwasher troubleshooting involves checking an air gap or garbage disposal for clogs. If you have one of these components, they share a common drain with the dishwasher. Consequently, if either become clogged with debris, food particles can block the shared drain and prevent dishwasher water from exiting. 

Always run a garbage disposal before starting your dishwasher to clear it of any food scraps that can clog the drain. If you have an air gap, clean it regularly by removing the cover and wiping away any visible debris with a paper towel.

If you still find your Bosch dishwasher not draining water or your dishwasher leaves dishes wet, Appliance Service Station can help. Schedule a fast and reliable repair with one of our expert technicians!