The short answer
On a Magic Clean dishwasher, a tub left full of water is most often a clogged filter and sump screen rather than a drain hose with no high loop, so waste water siphons back. The mechanical and blockage causes come first on a contract-built machine: there is less on the board to go wrong than in the water path. All three checks below are owner work, and not one of them needs a part.
What the owner observes
- It started the week the machine was refitted — Timing is evidence: a fault that begins with a service was caused by it.
- Complete silence where the drain should be — Silence points at the control and the cycle rather than at a blockage.
- It drains, but far more slowly than it used to — A gradual slowing is the filter loading rather than a sudden blockage.
- NEAR MISS — water on the floor rather than in the tub — Water outside the machine is a leak, and the leak page covers it.
Causes, most likely first on this brand
- A clogged filter and sump screen — A dishwasher recirculates its water many times in a cycle, so the filter works constantly rather than once. It loads far faster than owners expect, and it is the first restriction the water meets on the way out. It leads because it is the commonest cause by a wide margin, it takes minutes, and it decides which half of this list you need. These sit in apartments and rentals, often on a floor that was never levelled for them.
- A blocked air gap or a disposer knockout left in — Where the drain runs through an air gap on the sink, that fitting blocks with debris. Where it runs into a food disposer, a knockout plug left in place at installation blocks it completely from the first day. It sits here because lifting the air gap cap takes seconds and explains a great deal.
- A drain hose with no high loop, so waste water siphons back — The hose needs a rise in it before it reaches the waste connection. Without one — or trapped flat behind the machine — water runs back into the tub, and the fault starts the day the machine was last moved. It is last because the hose has not been touched in years.
Check in this order, and why
- Twist out the filter in the base of the tub and look at the mesh — A film you can see through is fine; a mat of debris is the fault. First, because it is the likeliest to end the job.
- Lift the cap off the air gap on the sink and look inside — Debris in the air gap blocks the drain as completely as anything in the machine. Second, once that is clean.
- Feel along the hose where it passes behind the machine — A flattened hose is easy to feel and almost impossible to see. Third, and by now the answer is usually in hand.
The owner-side checks
- Bail the standing water out, then clear the filter and sump by hand — Jug, cloth and a glove — broken glass in a sump is common.
Tools: jug, cloth, gloveAbout 25 min
- Clean out the air gap, or have the disposer knockout removed — A knockout left in at installation blocks the drain from day one.
Tools: clothAbout 20 min
- Free the hose and secure a high loop under the worktop — Use the clip the machine came with, or a cable tie to the cabinet wall.
Tools: cable tieAbout 20 min
- STOP — note whether the pump hums or stays silent — That one observation shortens the visit and often decides which part is ordered.
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. Close the water supply valve under the sink before opening any fitting — water arriving under pressure into a cupboard does more damage in an hour than the repair costs.
When to call a technician
The line is where the machine has to come out from under the worktop. The filter, the sump, the hose, the air gap and the programme are all yours; the pump and the control are not. On this brand generic assemblies shared across several nameplates, so a part is usually available but rarely branded.
The closest pages to this one
Generalized information
This page is written for the appliance class, not for one Magic Clean model line. Where a family- or model-specific page exists it is the better answer and it is linked below — go there first if your model is named. Not here: filter shapes, pump variants, hose routing, or part numbers.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
