One reason a pressure washer can use so much less water is its output pressure is about 50 times higher than a garden hose. Cleaners can be added to the pressurized spray to clean faster. The cleaner is poured into a small tank on the washer. Natural, environmentally safe cleaners are available.

The cleaning power of a pressure washer is rated by its maximum pressure and its water flow. Light-duty models have a pressure rating up to 2,000 PSI. Medium-duty, usually gasoline powered, are from 2,000 to 3,000 PSI.