Why water stays in the tub
Standing water at the end of a cycle on an owner-installed machine is an installation problem far more often than a pump problem. The drain hose high loop and the disposal knock-out plug account for most of these calls, and both are found in minutes without opening the machine.
What you are seeing
- Water remains in the tub at the end of every cycle.
- The machine drains slowly and leaves a shallow pool.
- Dirty water backs up into the tub from the sink.
- A gurgle at the sink whenever the machine drains.
- The drain runs but the level barely drops.
- Not this fault: Water on the floor rather than in the tub is a leak - read the water leak page.
- Not this fault: A cycle that stops before the drain step is a cycle fault.
Most likely causes, in Dencrest order
- Drain hose fitted without a high loop or air gap — Why ranked: First on an owner-installed machine. Without it the sink drains back into the tub, and the fingerprint is dirty water appearing after the machine has finished.
- Disposal knock-out plug never removed — Why ranked: Second, and it is the classic new-installation fault: a machine that has never once drained since the day it was fitted.
- Filter and sump blocked with food debris and grease — Why ranked: Third. On compact machines the filter is small and clogs quickly, giving slow drainage that gets worse over weeks.
- Drain hose kinked or crushed behind the machine — Why ranked: Fourth. Pushing the machine back into its space traps the hose, which shows as a fault that started right after the machine was moved.
- Drain pump blocked or failed — Why ranked: Last: real, but it is what remains after the four installation and maintenance causes above have been cleared.
What to check, in order
- Ask whether the machine has ever drained properly since it was installed. — Because: Never-worked points at the knock-out plug or the hose routing; used-to-work points at debris or a kink.
- Look at how the drain hose rises before it reaches the sink drain. — Because: A hose with no high loop siphons back, which is cause one and is visible without tools.
- Pull the filter and look at the sump for debris. — Because: This is quick, needs no tools on most machines, and clears cause three.
- Check the hose run behind the machine for kinks and crush points. — Because: Anything that started after the machine was moved is usually here.
Checks you can do safely
- Bail out the standing water with a cup and sponge the sump dry. — N: 1 — Tools: Cup, sponge — Time: moderate
- Twist out the filter, rinse it under a tap and clear the sump by hand. — N: 2 — Tools: None — Time: moderate
- Trace the drain hose and confirm it rises high under the counter before dropping to the drain. — N: 3 — Tools: Torch — Time: quick
- Ease the machine forward enough to check the hose is not kinked or crushed. — N: 4 — Tools: None — Time: moderate
- If the drain connects to a disposal, confirm the knock-out plug was removed when it was fitted. — N: 5 — Tools: Torch — Time: moderate
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. Standing water in a dishwasher holds broken glass and sharp debris - use a sponge and a cup rather than reaching blindly into the sump. Close the water supply before disturbing any hose or fitting. Never run the machine with the filter removed. Dry the floor before restoring power after any water work.
When this becomes a service call
The tub does not drain at all with a clear filter and a correctly routed hose. The drain pump is silent during the drain step. Water backs up from the sink into the tub whenever the sink is used. There is a burning smell from the pump area during the drain step.
Nearest pages
What this page does not cover
This is generalized information for dishwashers carrying the Dencrest Limited name. It does not separate built-in machines from countertop units fed by a faucet adapter, whose drain arrangements are completely different, and it names no model-specific pump or filter. Where a family- or model-specific page exists it supersedes this one.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
