The short answer
A Blomberg integrated dishwasher that will not drain usually has a loaded filter or a shared waste that is blocking upstream — commonly a disposer spigot left blind at installation, or a sink trap silting up. Check the filter, then the shared waste, before assuming the pump has failed.
What you observe
- Water standing in the sump at the end — The drain step did not complete.
- Water backing up into the sink or the machine — A shared waste blocked upstream of both.
- The pump audibly runs and nothing moves — A blockage in the hose or at the spigot.
- NEAR MISS — water under the plinth — That is a leak and belongs on the water-leak page.
Causes, most likely first on this brand
- A loaded filter and sump — First, and behind a furniture door the easiest to neglect: a filter packed with soil slows the drain long before it stops it, which is why this develops gradually.
- A blocked shared waste or a blind spigot — Second and very common on an integrated fitting: a disposer or trap spigot whose blank was never knocked out at installation leaves the machine with nowhere to drain, sometimes for years after the kitchen was built.
- A kinked or trapped hose in the cabinet — Third. The hose runs hidden behind the machine, and an appliance pushed back hard against it crushes it out of sight.
- A pump fault or a jammed impeller — Last, and the only one requiring service on an integrated machine that has to be drawn from its housing.
Check in this order, and why
- Fill and drain the sink and watch it — A slow sink names the shared waste immediately.
- Pull the filter and clear the sump — The most common cause and the fastest to fix.
- Check the waste spigot and the trap — A blind spigot is a classic installation legacy.
- Only then look at the hose route and the pump — Both need the machine drawn from its housing.
What an owner can safely check
- Switch off at the isolation switch and bail the sump — Find the switch in the adjacent cabinet before starting.
Tools: jug, sponge, clothAbout 25 min
- Rinse the filter and clear the sump — Glass and labels collect here unnoticed.
Tools: brush, torchAbout 20 min
- Clean the sink trap and the waste spigot — Grease and debris build where the two wastes meet.
Tools: bucket, wrench, brushAbout 40 min
- Check the spigot blank was removed at installation — On a newer kitchen this is the whole answer surprisingly often.
Tools: torchAbout 20 min
- STOP HERE if the sump refills and the waste is clear — Drawing the machine out is a service job.
Before you open anything
Safety
Switch the dishwasher off at its circuit before bailing the sump or opening the waste — a capacitor can hold a charge after the power is off, and an integrated machine's isolation switch is often hidden in a neighbouring cabinet. Expect standing water and put towels down. Take care of glass in the filter, and never mix drain chemicals with a dishwasher waste.
When to call a technician
Call when the filter is clean, the sink drains freely, the spigot is open and water still stands in the sump. Pulling an integrated machine out from under a worktop with a furniture door attached is awkward work, so ask what the visit includes. A burning smell during the drain step means switch it off and stop.
Nearest pages of this class
What this page does not cover
This page covers Blomberg integrated dishwashers as a class rather than one model line. Deliberately absent here: hose dimensions, pump and filter part identifiers, housing clearances and cycle timings, which differ by family and belong on the family or model page.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
