DIAGNOSIS Standing water indicates a drain pump failure, a clog, or a faulty check valve in the drain hose.
FIX Check the drain hose for kinks or clogs first. Disconnect the hose from the sink drain or garbage disposal and blow through it. Next, inspect the drain pump. Remove the lower kick plate and filter assembly. Manually check the pump impeller for debris (glass, pits). Clear any obstruction.
IF THAT DIDN'T WORK The drain pump motor itself may have failed. Listen for a humming sound during a drain cycle. No sound points to a dead pump motor. Replace the drain pump assembly.
HEADS UP Bosch models use a float switch in the sump. Ensure this switch moves freely and is not jammed by debris, which can also prevent draining.