PSI, or "pounds per square inch," refers to how much force a pressure washer is capable of producing to propel the water stream at the cleaning surface. For example, a pump spray bottle has high water force, but low water flow.
GPM, or "gallons per minute," identifies the amount of water a pressure washer uses to clear dirt and grime from the cleaning surface. An unrestricted garden hose illustrates the idea of high water flow and low water force.
When selecting a pressure washer, make sure to consider how often you plan to use it. If you plan to use your pressure washer frequently/daily, consider a model with an OHV engine and a commercial grade triplex pump for added performance and reliability.
There are three main types of pressure washer nozzles. Adjustable spray nozzles allow for an easy change of the spray pattern from pinpoint to wide fan spray. Quick connect spray tips have predefined spray patterns for precise control. The Briggs & Stratton ProjectPro™ nozzle system is a unique set of nozzles with preset pressure and flow settings for different projects.
Pressure washers equipped with a detergent injection system automatically siphon and mix cleaning detergents into the water stream for even more effective cleaning. For added convenience, some models come with onboard detergent storage tanks.