Before starting, ensure the dishwasher is and disconnected from its power source.

Most people stop at the bottom filter. But the drain line—the corrugated hose running from your dishwasher to the garbage disposal or sink trap—is a ribbed superhighway for biofilm. Food particles lodge in those ribs, harden, and create a concrete-like paste.

You have spent 90 minutes cleaning. Let's keep it that way. The exclusive prevention rules: