PartsCompat UK
Diagnosis Bosch

Why is my Bosch dishwasher not draining?

Water pooling in your Bosch dishwasher means either a blockage or pump failure. Follow these steps to identify which part needs replacing.

Difficulty: Easy
Time: 15 min

Most likely causes

  • 45% Blocked drain filter or trap trapping food debris and preventing water escape.
  • 25% Kinked or blocked drain hose restricting water flow from the dishwasher.
  • 20% Faulty drain pump unable to push water out of the tub.
  • 10% Blocked air gap or standpipe preventing drainage from the outlet.

How to diagnose it

  1. 1

    Remove and inspect filter

    Open the dishwasher door and locate the cylindrical filter at the bottom. Unscrew it anticlockwise and check for food, grease, or debris blocking the mesh.

    💡 Rinse the filter under hot water and use an old toothbrush to remove stubborn buildup.

  2. 2

    Check drain hose connection

    Locate the drain hose behind the dishwasher (usually grey or black rubber). Feel along its entire length for kinks, cracks, or compression points.

    💡 Run your hand from the dishwasher outlet to the sink connection to spot any damage.

  3. 3

    Inspect for standing water

    If water remains in the tub after 30 minutes, place a bucket under the drain hose and disconnect it. See if water drains freely from the hose.

    💡 If no water flows, the pump is likely faulty. If water flows, the blockage is upstream.

  4. 4

    Test the drain pump motor

    Listen near the base of the dishwasher during the drain cycle. You should hear a buzzing or whirring sound from the pump motor.

    💡 No sound means the pump motor isn't running. A humming sound with no water flow indicates a jammed impeller.

  5. 5

    Check air gap or standpipe

    If your sink has an air gap (chrome dome on the counter), unscrew the cap and look inside for debris. For standpipes, check the opening under the sink is clear.

    💡 Stubborn blockages in the air gap can be cleared with a straightened paperclip or plumbing snake.

⚠️ Always disconnect your appliance from mains power before starting any repair. If in doubt, consult a qualified engineer.

Parts you may need

pump

Drain pump assembly

OEM: 12009625

Complete pump unit with motor and impeller for Bosch dishwashers.

filter

Drain filter basket

OEM: 10002494

Cylindrical strainer basket that catches food particles and debris.

hose

Drain hose

OEM: 00622042

Reinforced rubber hose carrying wastewater from the pump to the sink outlet.

valve

Drain valve solenoid

OEM: 12014656

Electromagnetic valve controlling water release during the drain cycle.

FAQs

Should I run the dishwasher empty if the filter is blocked?
No. Clean the filter first, then run a short rinse cycle to flush remaining debris through the pump and hose.
Can a blocked drain hose be unblocked or does it need replacing?
Try flushing it with hot water from a kettle or use a plumbing snake. If it's kinked, straighten it carefully. Replace only if cracked or permanently damaged.
What does a faulty pump sound like?
A working pump hums and whirs during the drain cycle. A faulty pump either stays silent or makes a grinding noise without draining water.