The abbreviation “PSI” stands for pounds per square inch. It simply refers to the amount of pressure used to clean a surface.
PSI will vary depending on the pressure washer and the task at hand. For example, an electric pressure washer that you can use at home may reach around 1,000PSI; on the other hand, a heavy-duty pressure washer that is more suitable for industrial use can go up to 3,500PSI, or even higher.