The short answer
Water left in the bottom of the tub is nearly always a restriction somewhere in the drain path, not a dead pump. A pump that has failed outright is silent; a pump fighting a blockage hums, strains or pulses and still leaves water behind. Listen at the end of the cycle: a hum with no water movement points at a restriction or a jam, and complete silence points at power, the control or the pump winding. On a SPT dishwasher the cause that ranks first is filter and sump packed with soil.
What you observe
- The machine hums or pulses during the drain step but the level never falls — A pump working against a restriction, not a pump that has died.
- Dishes come out wet and the cycle seems to take longer than it used to — Drain steps that time out stretch the cycle before they fail it outright.
- A smell from the tub between cycles — Standing water plus trapped soil, which is the same fault seen a week later.
- NEAR MISS — the machine does nothing at all and the panel is dead — That is a power or control fault and belongs on the will-not-start page.
Causes, most likely first on a SPT dishwasher
- Filter and sump packed with soil — Food soil, labels and grease build into a mat across the fine filter until the pump can no longer pull water through it. It ranks first on a SPT dishwasher because a countertop machine has a short, tight path and a small pump, so a blockage stops it dead instead of slowing it down.
- Drain hose kinked, crushed or high-looped wrongly — The hose leaves the machine, is squashed behind the cabinet or under a plinth, and the pump cannot lift water over the loop. Second on this platform: the hose is the only part of the path that moves when the machine is fitted, pushed back or transported.
- Drain pump impeller jammed — A cherry stone, a shard of glass or a twist tie gets past the filter and locks the impeller, so the motor buzzes and nothing moves. Last, and the reason to work down the list rather than guess: the debris that gets past a neglected filter has nowhere else to go.
Check in this order, and why
- Lift out the filter stack and look at the sump beneath it — It is the commonest cause and it takes a minute, so nothing else is worth doing first.
- Pull the machine forward and follow the drain hose by hand end to end — A crush point found here saves taking anything apart.
- Listen at the end of the drain step for a buzz without flow — A buzz with no water movement is a jam, not a dead motor.
What an owner can safely check
- Remove the filter stack, wash it under a hot tap and clear the sump by hand — Wear a glove — broken glass and staples collect down there.
Tools: warm water, washing-up brush, gloveAbout 20 min
- Straighten the hose, re-seat the high loop above the sump and re-clip it — Do not let the hose rest on its own weight against the cabinet back.
Tools: torchAbout 15 min
- Run the disposer empty with cold water, then retry the drain step — If the machine is newly installed, check the knockout plug was removed.
Tools: torchAbout 10 min
- STOP at the point where the next check means live terminals or a panel removed — Everything past that line is a technician's work, however likely the cause above it looks.
Before you open anything
Safety
Unplug the machine or switch off its breaker before removing any panel — a capacitor can hold a charge after the power is off. Bail the tub before you reach into the sump: broken glass sits in there invisibly under the water.
When to call a technician
Call once you have cleared every restriction you can reach and the level still does not fall, and call straight away if the machine trips the breaker when the drain step begins. On a countertop machine, get a price before committing — the labour on a small machine is the same as on a large one, and the machine is not.
Nearest pages of this class
What this page does not cover
What this page covers is the dishwasher class as SPT builds it, not an individual family or model line. If a page exists for your particular family or model, it is linked above and it is the better answer — go there first when your model is named. Left out on purpose: part numbers, connector colours, disassembly order and torque values, because every one of those varies by family.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
