A pressure washer is an outdoor power tool that makes cleaning easier by using a high-pressure spray of water to clean a surface. A gasoline engine or electric motor drives a pump, which is supplied by your home’s water supply. The water enters the pump at about 50 PSI, is compressed (and thus pressurized) inside the pump, and exits the pump at as much as several thousand PSI, depending upon the unit. This high-pressure water travels through a hose to a spray gun. The nozzle at the end of the spray gun directs the high-pressure spray as you clean.

The force of the high-pressure spray loosens dirt and flushes it away. On more professional-grade models, the spray is even powerful enough to strip paint, which is useful in paint preparation. You can use many detergents with a power washer, too, for even more effective cleaning. And there are accessories you can buy that make cleaning even easier.