Answer first
On a Willz dishwasher, not draining usually comes down to the disposal knockout plug left in at installation, with a choked filter and sump next. Establish first whether the machine has ever drained properly, because a machine that never has is an installation fault rather than a failure.
What you actually observe
- Standing water in the bottom of the tub after a cycle — Usually with soil suspended in it.
- A smell when the door is opened — Water that never leaves the sump goes stale.
- NEAR MISS — the sink beside it also drains slowly — Then the house drain is the fault and the machine is doing nothing wrong.
Causes, most likely first on this platform
- The disposal knockout plug left in at installation — A machine that has never drained properly from its first cycle has this fault and no other. First on a recently installed machine in this class, and it is an installation fault rather than a machine fault: if it has never drained properly since the day it went in, the knockout plug is still in the disposal.
- A choked filter and sump — Standing water with food in it is the sump telling you it is full before it is telling you anything else. Second. A simple filter fills quickly and is rarely cleaned, and standing water with food in it is the sump telling you so.
- A kinked or crushed drain hose — Third: these machines get pushed into their opening rather than fitted into it, and the drain hose is what gets crushed against the cabinet back.
- Glass, a seed or a label in the drain pump — Fourth, and the point where an owner check ends: a pump that hums and moves nothing usually has something in it.
Check in this order, and why that order
- Establish whether the machine has ever drained properly — A machine that has never worked from its first cycle is an installation fault, not a failure. It goes first: top-ranked above, and free to rule out.
- Lift the filter out and look into the sump — Standing water with soil in it is the sump telling you it is full before it tells you anything else. Second: the next cause in the ranking, and this check separates it from the first.
- Pull the machine forward and look at the drain hose — A hose crushed against the cabinet back has usually been that way since installation. Third, once both checks above come back clean.
What an owner can safely check
- Check with whoever installed it whether the disposal knockout plug was removed — If the machine has never drained since day one, this is almost certainly why.
About 10 min
- Bail the standing water out, then remove and rinse the filter and screen — A jug and a sponge get the tub dry enough to see what is underneath.
Tools: jug, sponge, soft brushAbout 20 min
- Ease the machine out and straighten the drain hose — Keep the door shut while you move it, and watch the supply line so it does not snag.
About 20 min
- STOP HERE if the next step needs the machine unplugged and a panel removed — Anything behind the outer panel of a machine holding water and mains wiring is a service call.
Before you take anything off
Safety
Unplug the machine or switch off its breaker before removing any panel; a capacitor can hold a charge after the power is off, and this machine holds water and mains wiring in one cabinet. Never defeat the door latch switch, and never reach into a sump or a drain pump that is still plugged in: broken glass goes through a rubber glove.
Where an owner check ends
Call once the filter, the hose and the air gap are clear and water still sits in the tub, because the pump is the next item and it is behind the panel. Call sooner if water is reaching the floor as well, because a machine that cannot drain will eventually overflow. On a cost-reduced platform the cheap repairs are worth doing and the expensive ones rarely are, so get the cause named before agreeing to anything.
Where to go next in this class
What this page does not cover
This page is written for the Willz dishwasher as a class, not for one family or model line. Where a family- or model-specific page exists for your unit it is linked here, and it is the more specific answer. Not here: part numbers, wiring colours, torque figures, panel sequences and component ratings, which differ by family.
Links: - [Willz dishwasher leaking onto the floor: where it starts](/blog/willz-dishwasher-water-leak) - [Willz dishwasher leaving dishes dirty: what to check first](/blog/willz-dishwasher-cleaning-performance) - [Wizard dishwasher not draining: water left in the bottom](/blog/wizard-dishwasher-drainage-failure)
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
