A dishwasher that won't drain leaves standing water at the bottom of the tub. It's frustrating, but the fix is usually straightforward. Here are the 6 most common causes, in order of likelihood.
Food debris accumulates in the filter at the bottom of the tub. When it's clogged, water can't flow to the drain pump.
Fix: Remove the lower rack. Locate the filter (a circular or mesh screen at the bottom center). Twist or lift it out. Clean it under running water. Check the area around the filter for debris. Replace the filter and test the drain cycle.
The drain hose (at the back of the dishwasher) can get kinked, clogged with grease, or pinched. The hose should have a high loop (looped up and clamped to the underside of the counter) to prevent siphoning.
Fix: Unplug the dishwasher. Pull it forward. Disconnect the drain hose from the sink drain or garbage disposal. Check for kinks, clogs, or pinches. Run water through the hose to clear any blockage. Reconnect with the proper high loop.
If the dishwasher drains into a garbage disposal, the drain port in the disposal may be clogged. Some installations also have an air gap on the counter that can clog.
Fix: If your dishwasher drains into a disposal: remove the rubber plug from the disposal's dishwasher inlet. Clean out the drain port with a brush or pipe cleaner. If there's an air gap on the counter: remove the cap and clean out the air gap chamber.
The drain pump pushes water out of the tub and through the drain hose. When the pump motor burns out or the impeller is jammed, water won't drain.
Test: Listen for the pump running during the drain cycle. If you hear a hum but no water movement, the impeller is jammed. If you hear nothing, the motor has failed. Unplug the pump motor and check for continuity (should read 10-50 ohms).
Fix: Replace the drain pump ($30-80). While you're in there, check the impeller for debris and spin it by hand to make sure it turns freely.
The check valve (a small flap or ball) inside the drain pump prevents water from flowing back into the tub. When it's stuck closed or clogged with debris, water can't drain.
Fix: Access the drain pump (usually at the bottom front of the dishwasher). Remove the check valve housing. Clean out any debris. Make sure the valve flap or ball moves freely. Reassemble and test.
The control board sends power to the drain pump. If the float switch (which detects water level) is stuck or the control board isn't sending the signal, the pump never activates.
Test: Check the float switch (usually near the bottom of the tub). It should move freely up and down. If it's stuck, clean it or replace it. If the float works, the control board may not be sending power to the pump.
Fix: Replace the float switch ($10-25) or the control board ($80-200).
For step-by-step repair procedures, see our Dishwasher Not Draining Repair Guide.
For component identification, see our Component Reference.