The short answer
Water standing above the filter at the end of a cycle on a Bosch SPS-series dishwasher is almost never the drain pump, whatever the noise suggests. On this platform the path is short and the things that close it are ranked by the compact cabinet and by how the machine was plumbed in: the softener reservoir and a bar handle both change which end of that path you should look at first. A film of water that leaves the filter dry is normal and is not this fault.
What you observe
- The sink beside it drains slowly too — That moves the whole diagnosis out of the machine and under the worktop.
- Water reappears in the tub hours after a cycle — Not a drain failure at all but a back-feed, and it is diagnosed from the other end.
- Water covering the filter when the cycle ends — That is the symptom. A film below the filter is normal and keeps the seals wet.
- A hum from the base with nothing moving — The pump is being asked to work against something it cannot shift.
- NEAR MISS - the machine drains continuously and refuses to fill — That is leak protection reporting water beneath the tub, not a drain fault. It belongs on the leak page and it does not get better by cleaning a filter.
Likeliest causes here
- The filter and the sump beneath it — Everything the wash lifts off the dishes arrives here, and the drain path starts on the far side of it. It leads here, and not by default: the sump on this cabinet holds less than a full-size one, so it closes on less.
- Something solid in the drain pump impeller — Glass, a fruit stone, a bottle label or a bone fragment reaches the impeller and jams it, and the motor hums against it. It sits second on this family because the clearance in this pump is tighter than the full-width machines.
- The air gap blocked, or a disposer knockout left in place — The path above the worktop closes as readily as the path below it, and a new disposer that has never had its plug punched out blocks it completely. Third here. A fixed installation that has drained before rarely develops it.
- A non-return flap held open by debris — Once the flap cannot seat, what the pump sent out comes back in. Last on this family, and deliberately so: uncommon, and it presents as water returning rather than water never leaving.
- Where this ranking departs from the brand-generic page — The cause that moves is the filter and the sump beneath it. It leads on this family because the cabinet fills a narrower opening, so the sump, the filter and the clearance round the spray arms are all tighter. That is a property of the platform rather than of the brand, which is why the page above this one cannot rank it the same way.
Check in this order
- Bail the tub out, then twist the filter assembly free — Clear the sump by hand and look for glass. What is under the filter is the diagnosis more often than anything downstream. It leads on these models because the construction puts it within reach before anything else on the list.
- Reach into the sump opening and turn the impeller — It should move freely. Anything gritty or seized is what the hum has been fighting.
- Lift the air gap cover on the worktop and clear it — If a disposer has been fitted, confirm its dishwasher knockout was actually removed.
- Check the flap where the hose meets the waste — Debris across the seat lets back-feed through, and that reads as a drain fault from the front.
Before you open anything
Safety
Unplug the appliance or switch off its breaker before removing any panel or reaching under the tub - a capacitor can hold a charge after the power is off. Bail the standing water out before you start rather than after, assume broken glass in the sump, and wear a glove for the impeller. Do not drag a built-in machine out with its supply still connected.
When to call
Everything inside the tub is owner ground on these models, and so is everything under the sink. The line is the base plate: a pump that is silent when it should run, a control that never calls for a drain, or a leak-protection state that will not clear are all diagnosed with a meter and the machine tipped.
Nearest pages
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
