Definition
The wash pump (sometimes called the circulation pump on European dishwashers) is the high-volume electric pump that powers the spray arms in a dishwasher. It draws filtered water from the sump and pushes it through the upper, middle, and lower spray arms at enough pressure to scrub food off dishes. When it fails, the dishwasher runs the full cycle but dishes come out dirty.
What It Does
After the inlet valve fills the sump with hot water and detergent, the wash pump motor energizes and spins an impeller inside the pump housing. The impeller pressurizes water and forces it up through a manifold to the spray arms, which spin from the reaction force of the water jets. The pump runs continuously through wash and rinse phases. Modern Bosch and Samsung dishwashers use brushless DC motors with variable speed for quieter operation.
Where It’s Located
Under the dishwasher tub at the center, where the sump and filter assembly sit. Accessed by pulling the dishwasher forward and removing the bottom access panel. Brand examples: Whirlpool/KitchenAid use WPW10510667 series; Bosch uses 00755078; Samsung uses DD81-01262A; LG uses 5859DD9001A.
Common Failure Signs
- Dishes come out dirty even on a heavy cycle
- Loud grinding or humming from under the dishwasher during operation
- Spray arms barely spin or do not spin at all
- Pump motor hums but no water moves
- Error codes: Bosch E09, Samsung 9E, LG nE
Typical Replacement Cost
$280–$520 including parts and labor. Wash pumps are $140–$320 in parts. On Bosch and Samsung dishwashers the pump is often integrated with the sump and must be replaced as an assembly.
DIY vs Pro
Pro repair. Replacement requires pulling the dishwasher out from under the counter, disconnecting water and electrical, and laying it on its back to access the pump. Confirming the pump (versus the motor capacitor, control board, or a clogged sump) requires diagnosis with a multimeter. Book dishwasher repair.
Need this part replaced? Call (720) 447-8577 for same-day dishwasher repair in the Denver metro area.