The short answer
Standing water is usually the filter, the sump or the drain hose route. On a recently installed machine, suspect the installation first: a missing high loop or a disposer knockout plug still in place will stop it draining from day one.
What you find
- Water covering the tub floor at the end of a cycle — The basic symptom.
- Dirty water that smells — It has been standing for more than one cycle.
- The pump is audible but nothing leaves — A restriction rather than a dead pump.
- Water appears in the tub between uses — Back-flow from the sink, which is a hose routing problem.
- It has never drained properly since installation — Look at the installation, not the machine.
- Not this fault: water on the floor — That is the leak page.
Ranked by what we find
- Filter and sump blocked with food debris — First on an established machine.
- Drain hose kinked, or no high loop fitted — First on a machine that never drained well.
- Disposer knockout plug left in place — Third, and it stops drainage completely on a new installation.
- Air gap or waste spigot blocked — Fourth, and it shows as a slow drain.
- Pump impeller jammed by glass or a fruit stone — Fifth, and it usually follows a breakage in the machine.
- Drain pump failed — Last, after the five above.
Work through it in this order
- Bail out the standing water and remove the filter — You cannot inspect anything through dirty water.
- Check the sump and turn the impeller gently by hand — It should move freely.
- Look under the sink at the hose route and the high loop — Installation faults are visible and free to correct.
- Check the disposer connection if the machine is newly fitted — The knockout plug is a classic first-install fault.
Owner checks
- Scoop out the standing water with a cup and a sponge — Work with a bowl; there is more water than it looks.
Tools: cup, spongeAbout 20 min
- Remove the filter assembly and clean it thoroughly — Rinse under a tap and check the mesh is clear.
Tools: brushAbout 15 min
- Look into the sump for glass, stones or labels — Wear gloves; broken glass hides there.
Tools: gloves, torchAbout 10 min
- Check that the drain hose rises to a high loop under the counter — No loop means sink water can flow back into the tub.
Tools: torchAbout 15 min
- If it drains into a disposer, confirm the knockout plug was removed — Common on newly installed machines.
About 15 min
- Stop before removing the pump — It sits beneath the tub among mains connections.
Standing water and sharp objects
Safety
Unplug the appliance or switch off its breaker before removing any panel. A capacitor can hold a charge after the power is off. Wear gloves when reaching into a sump, because broken glass is the most common thing found there. The standing water may be hot, and it may contain detergent, so avoid skin contact and wash afterwards.
When to call
Call when the filter and sump are clean, the hose is correctly routed and the pump is silent when it should run, because the next step is removing the pump. Call a plumber instead if the sink waste itself drains slowly, since the dishwasher shares that pipework. On a new installation, call the installer: a missing high loop or an unremoved knockout plug is their responsibility rather than a fault.
Related pages
Page scope
Generalized across the dishwasher families under this badge; where a family-specific or model-specific page exists it is the narrower answer. Not here: pump part numbers, hose diameters, air gap specifications and the installation standards that vary by region.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
