Dishwasher left with water in the bottom
Standing water in the base of the tub is the most common dishwasher complaint there is, and the cause is usually reachable with your hands in about fifteen minutes.
What it usually means
A dishwasher is meant to finish dry, or near enough. Water lying in the bottom of the tub means the machine either could not pump out or was never able to start, and the good news is that the parts responsible sit at the bottom of the tub where you can reach them without tools.
It helps to know what is actually down there. Under the bottom basket is a filter assembly, usually a coarse plastic cup with a fine mesh cylinder inside it. Everything that comes off your plates ends up there — labels off jars, seeds, bits of rice, fragments of glass — and it is designed to be lifted out and rinsed. Manufacturers expect you to do it. A great many people have never taken one out in the life of the machine.
Below and behind the filter is the drain pump, and after that the waste hose, which usually joins the kitchen sink waste under the cupboard. A blockage anywhere along that run produces the same symptom, and the last part of it is not the machine's fault at all.
One thing to establish before you start: a small amount of clean water sitting in the recess around the filter is normal and by design. It keeps the seal from drying out. It is standing water above the tub floor, dirty and covering the filter, that means something is wrong.
How to narrow it down
Work through these in order.
Is the water clean or dirty?
Dirty water with food debris in it means the machine ran and could not drain. Clean water that appeared without a cycle running suggests the inlet valve is passing water in slowly, which is a different fault and worth mentioning when you call.
When did you last clean the filter?
If the answer is never, or you did not know there was one, start there. It is under the bottom basket, it twists out by hand, and it accounts for an enormous share of these complaints on its own.
Does the kitchen sink drain normally?
Most dishwashers discharge into the sink waste. If the sink is slow, the blockage is in your plumbing rather than the appliance, and clearing the sink trap will fix the dishwasher too.
Has anything been fitted under the sink recently?
A new sink, waste disposal or trap is a classic cause. If a waste disposal unit was fitted, the blanking plug on its dishwasher spigot must be knocked out — if it was left in, the machine has nowhere to pump to and never will until it comes out.
Can you hear the pump trying?
A humming or straining noise with no water moving usually means the pump is running against a blockage or something is jammed in the impeller. Silence at the point it should be draining points more towards the pump itself or its supply.
When it is urgent
Take care
What it costs
Typical repair cost
£0–£180
Typical UK prices including parts and labour, updated August 2026. Your quote may differ.
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