Dishwashers

Dishwashers were one category, not a cubic-foot tree. The split that changes the work is built-in, drawer, or portable.

The 24-inch opening

A built-in tub slides under the counter. Hot water comes from the sink supply, the drain hose ties to the sink drain or the disposal, and the power lands in the cabinet beside the tub. Panel-ready doors take a slab that matches the cabinets. A finished door does not. Measure the opening height at the toe-kick. A thick replacement countertop is a common reason a new tub will not roll in.

Soil, film, and standing water

Food stays in a filter. If that filter is packed, the next cycle sprays the same water. A pool left in the bottom after the cycle means the pump did not empty the tub: the hose is kinked, the air gap is clogged, or a new disposal still has the knockout plug in the nipple. White film on glass is usually hard water and low rinse aid. More detergent on top of hard water makes the film worse.

Drawers and portables

A drawer machine is one or two pull-out tubs. It fits a kitchen that cannot give up a full 24-inch bay. A portable rolls to the faucet and connects there. It is the machine for a kitchen that was never roughed in, and the wash system inside can look like a built-in while the hookup does not.