Dishwasher won't drain — water left in the bottom
Standing water in the base after the cycle. Nearly always a blocked filter, a blocked sink waste, or — on a newly installed machine — a blanking plug that was never knocked out of the waste spigot.
You can fix this yourself
No special tools or qualifications needed
About 1 hr to work through
Free to £160
DIY: Up to £40 in parts
Before you start
Electrical safety: Unplug the machine before putting your hands into the sump.
Sharp objects: Broken glass collects in the dishwasher filter. Look before you reach, and wear gloves.
What causes it, most likely first
Blocked filter assembly
Most likelyThe cylindrical filter and flat mesh in the tub floor collect grease, labels and seeds. Low-temperature eco cycles do not melt fat, so it varnishes on and needs a hot scrub rather than a rinse.
How to check: Twist the filter out and hold it up to the light. If you cannot see through the mesh, that is your fault.
Blanking plug still in the waste spigot
CommonSink waste spigots ship with a moulded plug that must be knocked out during installation. If the machine has never drained properly since it was fitted, this is almost certainly why.
How to check: Disconnect the drain hose at the spigot into a bucket and look inside for an intact plastic blank.
Blocked sink trap
CommonA fat-blocked kitchen trap backs up and stops the dishwasher draining even when the machine is clear.
Kinked drain hose
CommonSquashed behind the machine when it was pushed back into its housing.
Jammed drain pump
OccasionalGlass fragments or a fruit stone stall the impeller. There is usually a removable cover in the sump floor giving access.
Drain pump£15–£40 for the partDIY with care
What to check, in order
Unplug and bail out the water
Scoop the standing water from the sump with a cup, finishing with a sponge.
10 minCup, SpongeDeep-clean the filter stack
Twist the cylindrical filter anticlockwise and lift it out, then lift out the flat mesh below. Wash both in hot soapy water with a brush until light passes evenly through the mesh.
15 minWashing-up brush, GlovesCheck the waste connection under the sink
Pull the machine out and disconnect the drain hose at the sink spigot into a bucket. Look inside the spigot for the blanking plug. Clean the sink trap while you are there.
20 minBucket, ScrewdriverClear the drain pump
With the filters out, remove the small cover in the sump floor and turn the impeller with a finger. Remove any glass or debris jamming it.
10 minTorch, GlovesReassemble and run a rinse cycle
Refit the filters, locking the cylindrical one in with a positive twist — running without it seated lets debris straight into the pump. Restore power and run the shortest programme.
10 min
Need an engineer for this?
We list 75 dishwasher repair businesses across the UK. Diagnostic callouts typically start around £55, and many will put that towards the repair if you go ahead.
- 01493 290698Appliance Maintenance LtdVerifiedGreat Yarmouth
- 0118 9420 145Reading
- 07766 426665DW AppliancesVerifiedAberdeen
Parts you might need
Typical UK prices for the part alone, before fitting. Worth knowing before you accept a quote — the part is often a small share of what a repair is priced at.
Drain pump
Empties the dishwasher sump at the end of the cycle.
£15–£40
Worth repairing, or replace it?
At the top of this range the repair costs a significant share of a graded replacement, which typically starts around £190. Worth getting the quote first, then deciding — on a machine under about five years old a repair usually still wins.
Is there an error code on the display?
If your dishwasher is showing a code, that will narrow the diagnosis a lot further than symptoms alone.
Look up your error code