Dishwasher Making Noise

Checks you can do safely before you call

1. Turn the power off first. Cut power at the breaker, or pull the plug under the sink. Never reach into the tub or the sump with the power on. If the dishwasher has just finished a cycle, wait for it to cool, because a bare heating element along the bottom of the tub can still burn.
2. Spin the spray arms by hand. With the racks loaded as usual, turn each arm slowly. Anything it touches, such as a pan handle, a tall cutting board or a utensil through the rack, will knock during the wash.
3. Check the arms for play. With the power still off, lift out the lower arm and make sure the upper one is clipped or screwed on tight. Look for cracks and for a hub that wobbles.
4. Look in the sump. Take out the filter assembly and, wearing gloves, check the opening below it with a flashlight for glass, bones, pits or labels. Use tongs rather than fingers where you can't see.
5. Wet a dry seal. After the dishwasher has sat unused, pour about a quart of water into the bottom of the tub, close the door, restore the power and run a rinse.
6. Note when the noise happens. Run a cycle and note whether the sound comes during the fill, the wash or the drain. That narrows the cause before anyone takes the machine apart.

When to call a technician

• Grinding or rattling continues with the sump and the arms clear.
• The dishwasher hums but doesn't drain, or hums with no spray at all.
• The noise gets louder week by week, or you smell hot plastic. Turn the breaker off and don't run the dishwasher again before a technician sees it.
• Water stays in the tub along with the noise; see dishwasher not draining.
• The pipes bang hard when the fill stops. A plumber can fit a water hammer arrestor on the line.

What happens at the diagnostic visit

The technician runs the dishwasher through fill, wash and drain to hear the noise at its source, then inspects the wash and drain pump impellers, the motor bearings, the spray arms and their mounts, the inlet valve and the sump for foreign objects.

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. You get the repair price first, and the decision stays yours. Our dishwasher repair page covers the other faults we fix.

Brand and model notes

• Bosch: a rattle or grind as the water drains points to the drain pump impeller, and on models with a display a jammed pump shows E25. With the power off, the cover under the filter lifts so you can check for glass. See Bosch.
• Whirlpool, KitchenAid and Maytag: some models have a hard food chopper in the sump, including Maytag Dual Power Filtration models and older self-cleaning designs. It makes some noise as it works, and glass or a bone caught in it grinds much louder. The owner's manual says whether yours has one. See Whirlpool, KitchenAid and Maytag.
• LG: Inverter Direct Drive models run quietly, so a new grinding sound points to debris in the pump or a worn motor, and an LE code means the motor isn't running properly. See LG.