Why won't my dishwasher drain and what should I do?

A clogged drain is the most likely cause of water not pumping out of the tub. Check and clean the air gap if your dishwasher has one, verify your kitchen sink is draining properly, and if the dishwasher drains into a garbage disposer, run the disposer clear. If the sink drains poorly, you may need a plumber. (Page 20)