Dishwasher Not Cleaning Dishes

Checks you can do safely before you call

1. Switch off the dishwasher and let it cool before you take it apart. Turn off its breaker or pull its plug under the sink. Right after a cycle, give the tub time to cool before you remove the racks, the spray arms and the filter, since some models have an exposed heating element in the floor of the tub that holds its heat.
2. Clean the spray arms. Lift out the lower arm, and unclip or unscrew the upper arm as the owner's manual shows. Rinse them and clear each hole with a toothpick, not a metal pin that can widen it.
3. Rinse the filter. Take the filter assembly out of the tub floor, wash it in the sink with warm water and a soft brush, and refit it until it locks. A filter left loose lets debris through to the pump.
4. Start with hot water. Make sure the supply valve under the sink is fully open, because a half-closed valve starves the fill. If the valve is stiff, don't force it: an old valve can start leaking at the stem, and that is a job for the technician or a plumber. Once the power is back on, run the kitchen tap until the water is hot before you start a cycle.
5. Use the right detergent. Use fresh dishwasher detergent, never hand dish soap, and fill the rinse aid dispenser. Keep detergent sealed and dry, because clumped powder doesn't dissolve.
6. Load for the spray. Face the dirty side of plates toward the center, keep tall pans from blocking the arms, and spin each arm by hand before you close the door.

When to call a technician

• Dishes stay dirty with clean arms, a clean filter and hot water at the tap.
• The wash sounds weaker or quieter than it used to, which points to the wash pump.
• Dishes and the tub are cool to the touch at the end of a hot cycle.
• The detergent door stays shut, or the cycle skips steps or ends early.
• Grit keeps coming back because the water drains slowly too; see dishwasher not draining.

What happens at the diagnostic visit

The technician runs a cycle and watches the fill level and the spray, measures the water temperature, and tests the wash pump, the heater and its sensor, the detergent dispenser, the diverter that switches water between the arms, and the spray arm feed. Spray arms and the filter are checked for scale and damage, so you know whether cleaning, a part or a pump is the answer.

The diagnostic visit is $89 for a standard residential appliance and $129 for a built-in unit or commercial equipment; a premium brand on its own doesn't make an appliance built-in. The repair is priced before it starts, and nothing is done without your go-ahead. See our dishwasher repair page for the brands we work on.

Brand and model notes

• Bosch and Thermador: both are built by the same company on a shared platform, and on current models the heater sits inside the circulation pump, so cool, greasy dishes at the end of a cycle point to that heat pump, its temperature sensor or the control that drives it. Bosch dries by condensation, so wet or spotty glasses call for rinse aid before any part is changed. See Bosch and Thermador.
• Miele: the filter combination and the spray arms come out for cleaning. On G 7000 models with AutoDos, make sure the PowerDisk is seated and not empty before blaming the wash. See Miele dishwasher repair.
• Samsung: WaterWall models wash the lower rack with a sliding vane that moves along the floor of the tub. A utensil or a plate in its track stops it and leaves dirty patches. See Samsung.
• LG: QuadWash models use multi-motion spray arms. Take them out and rinse them with the filter when results slip, and check that the lower arm turns freely. See LG.