The short answer
On Blomberg DWT dishwashers this symptom narrows faster than it does at brand level, because the construction of this family rules some causes in and others out early. Before suspecting the pump, check the one connection almost every installation gets wrong — the disposer knockout plug. Listen during the drain step — a humming pump and a silent one point in completely different directions.
What you observe on these models
- A gurgle from the sink whenever the machine drains — The shared waste line is struggling with the flow rate.
- The pump hums during the drain step but the level does not drop — Powered and obstructed rather than failed.
- The machine drains but leaves a pool around the filter — Normal sump water in some designs; excessive if it covers the filter.
- NEAR MISS — the dishes are dirty but the tub drains — That is a cleaning fault, not a drainage one.
Causes, most likely first on this family
- Drain pump jammed by glass or debris — Fifth, and it is often found in the same inspection as the filter since the two are adjacent.
- Sink waste or air gap restricted — Fourth, because an air gap fitting on the worktop blocks with debris and is easily missed.
- Drain hose kinked, crushed or wrongly routed — Third, and a missing high loop lets sink water siphon back into the tub, which reads as a failure to drain.
- How this ranking departs from the brand-level article — The brand-generic page ranks purely by frequency. On this platform the component that sits behind the most accessible panel moves up, because confirming it is quick and confirming the others is not — that changes the practical order even where the underlying frequencies are similar.
Check in this order, and why
- Check whether the machine has ever drained properly — A machine that has not drained since the day it was installed has a plumbing fault, not a worn part.
- Ask whether the sink drains normally — A slow sink and a dishwasher that will not drain are one fault in the shared waste line, not two faults.
- Lift out the filter and look at the sump below it — Debris, glass fragments and labels collect there, and the drain opening is underneath.
- Why this order suits these models — The sequence above is chosen for this family's construction: each step is picked to eliminate as much as possible before anything has to come apart, so the checks that need no panel removed are done first and the ones that do are left until they are the only possibility remaining.
Before you open anything
Safety
Isolate power and water first, in that order, and put a towel down before you tilt anything. A dishwasher holds more water in its sump than it looks like it should, and it goes where the floor slopes.
When to call a technician
Bring somebody in at once if the machine trips its breaker, if water has reached the floor under the cabinet, or if it runs a cycle without ever heating. Those three are not worth another test cycle at home.
Other faults covered for this family
What this page generalizes over
This page covers the Blomberg DWT dishwashers as a family rather than one model. The models in it are close enough to share a diagnosis, but not identical, so where a detail depends on the individual model — a component position, a part number — it is not stated here. The family pages and the brand-level article linked below give the surrounding context.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
