Portable pressure washers work by taking water from any source and power the electric motor of the washer. Firstly, the pressure washer takes the detergent and mixes it with water. You will find that some of the washers heat the water to around 155 degrees. Then, the pump of the washer squirts out the water by using high-pressure of the jet. By switching the nozzles, you can customise what kind of water flow you want depending on the cleaning task.