The short answer
Standing water is usually the filter or the sink waste rather than the pump. Run the sink tap hard and watch inside the machine, then pull the filter - between them those two checks settle most of these.
What you actually see and hear
- Water above the filter at the end of every cycle — It could not pump out, or what it pumped came back.
- The sink drains slowly as well — A shared blockage. The dishwasher is only reporting it.
- The pump is audible but the level hardly moves — A restriction rather than a dead pump.
- It drains, then refills between stages — A siphon, from a missing or collapsed high loop.
- NEAR MISS - a little water always in the sump — Normal, and deliberate, to keep the seals wet.
Causes, most likely first on this machine
- Blocked filter and sump — First. Everything that leaves a plate ends up here, and a loaded filter slows drainage long before it stops it.
- Sink trap, waste or disposer connection — Second. The machine drains into the sink waste, so a slow trap is a slow dishwasher.
- Disposer knockout plug still fitted — Third, and unmistakable when it applies: a machine that has never drained since it was installed.
- Drain hose kinked or missing its high loop — Fourth. A hose lying flat siphons, and a kinked hose behind the cabinet blocks.
- Drain pump or check valve — Last. Pumps fail, but the plumbing in front of them fails more often.
Check in this order, and why
- Run the sink tap hard and watch inside the tub — Water rising in the machine is a shared-waste problem.
- Pull the filter and clear the sump — The most likely internal cause and the easiest.
- Check the sink trap and the disposer connection — Especially if the sink is slow too.
- Trace the drain hose behind the cabinet — Looking for a kink and for a proper high loop.
What an owner can safely check
- Bail the standing water out with a jug and sponge — First, so you can see and reach the filter.
Tools: jug, sponge, towelsAbout 15 min
- Remove and clean the filter and clear the sump by hand — Wear a glove: glass chips end up here.
Tools: gloves, brushAbout 20 min
- Clear the sink trap — A slow sink is a slow dishwasher, and clearing it often fixes both.
Tools: bucket, wrenchAbout 30 min
- Check the drain hose is looped high and not kinked — Behind the cabinet is where it gets crushed.
Tools: torchAbout 20 min
- Run a short cycle and watch the drain stage — Confirms the fix before you put everything back.
About 30 min
- STOP HERE before removing the pump or opening the sump housing — Wet work near live terminals.
Before you open anything
Safety
Unplug the appliance or switch off its breaker before removing any panel - a capacitor can hold a charge after the power is off. A dishwasher sits in a wet cabinet with a live connection behind it, so switch off at the breaker before pulling it out, and close the isolating valve under the sink before touching a hose. Let a hot cycle cool before reaching into the tub.
When to call a technician
Call when the filter is clean, the sink drains freely, the hose is looped and clear and the tub still holds water - that leaves the drain pump or the check valve. Call a plumber instead if the sink is slow as well. If the machine has never drained since it was installed, say so: that points straight at the disposer knockout plug and saves everyone a wasted visit.
Nearest pages of this class
What this page does not cover
This page is written for the full-size tall-tub dishwasher class, not for one family or model line. Where a brand- or model-specific page exists for your unit it is the more specific answer and it is linked above, so go there first if your machine is named. What is deliberately not here: spray arm and pump part numbers, chopper blade specifications, hose routing diagrams and control diagnostics, all of which differ by family and belong on the page for that family.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
