It is necessary to point out that there exist two types of pressure washers, which basically differ not with the way they work but rather with the way they are powered. Both electrical powered and gas-fueled engines in this device are intended to produce energy for powering a water pump. This is done in order to help the pump accelerate the water that comes from a garden hose to produce a jet of water. You need to pull the trigger and this device will mix the water from the hose with air to form the jet coming out of the nozzle. Overall, this principle of work is very similar to the technology of a water gun that is used at car washes.