Fix a Dishwasher That Won't Drain

Category: Appliances · Difficulty: Intermediate · Time: 1.3h · Estimated cost: $30

Tools needed

Bail standing water
Use a turkey baster or cup to bail water out of the tub down to a wet film.
Duration: 15 min
Clean the filter
Remove the lower rack. Twist out the cylindrical filter at the bottom. Rinse food and grease off in the sink under hot water.
Duration: 10 min
Check the air gap or high loop
If you have an air gap on the sink deck, pop it off and clear debris with a shop vac. If you have a high loop instead, confirm the drain hose loops above the disposal inlet.
Duration: 15 min
Disconnect drain hose at disposal
Place bucket under the disposal inlet. Loosen the clamp and pull the dishwasher drain hose off. Blow through it from the dishwasher side — feel for free airflow.
Duration: 15 min
Punch out the disposal knockout plug
Most disposals ship with a plastic knockout plug in the dishwasher inlet. New disposals often have it still in place. Look inside with a flashlight — knock it out with a screwdriver if you see it.
Duration: 10 min
Reconnect, run drain cycle
Reattach hose with clamp. Run a drain-only cycle. Watch for water moving through the hose.
Duration: 15 min

Cut power at the breaker before reaching under the dishwasher.
A dishwasher that drains slowly + smells bad usually means the high loop is missing — fix that or sewer gas backs up.

If the drain pump won't run at all (no hum, no whir) the pump is dead. Pump swaps require pulling the dishwasher — call an appliance tech.