A pressure washer or power washer is a high-pressure mechanical sprayer used to remove loose paint, mold, grime, dust, mud, and dirt from surfaces and objects such as buildings, vehicles and concrete surfaces. The volume of a pressure washer is expressed in liters per minute, often designed into the pump and not variable. The pressure, expressed in pounds per square inch (psi) or bar, is designed into the pump but can be varied by adjusting the unloader valve.

The basic pressure washer consists of a motor that drives a high-pressure pump, a high-pressure hose and a trigger gun. Nozzle is used to increase the velocity of water, a pressure washer creates high pressure and velocity. The pump cannot draw more water from the pipe to which the washer is connected than that source can provide: the water supply must be adequate for the machine connected to it, as water starvation leads to cavitation damage of the pump elements.

Different types of nozzle are available for different application. Some nozzles create a water jet that is in a triangular plane (fan pattern), others emit a thin jet of water that spirals around rapidly (cone pattern). Nozzles that deliver a higher flow rate lower the output pressure. Most nozzles attach directly to the trigger gun


High Pressure Washers are classified into following groups based on the type of fuel/energy they consume.

• Electric • Diesel • Petrol • Ultra high pressure • Hydraulic high pressure • High-pressure steam cleaner