Tabletop dishwashers work exactly the same way as their hard-wired counterparts, and the only difference in the two models is the size and location. While tabletop dishwashers are more compact and weigh less than a conventional dishwasher, their respective engine and drain components are the same. Tabletop models have electronic or manual control panels that allow the user to select a variety of settings.
A tabletop dishwasher uses a drain hose, or an intake valve, that connects to a water source and an external plug for a power supply. The dishwasher's pump system is powered by an electric motor that switches between filling and draining the unit. The motor also powers pressurized spray nozzles that remove food and debris from dishes. According to HowStuffWorks, a dishwater motor runs in one direction and uses a solenoid to reverse the pump action and to power sprayer arms through the wash and rinse cycle.
Tabletop dishwashers are smaller, more energy efficient alternatives to full-sized models that do not need to be stored under cabinets or in closets. According to About.com, they are more suitable for households of two or three people and the top can double as counter space, making them effective space savers.