Pressure Washing Basics: How It Works

Pressure or power washers use high levels of water pressure (often measured in psi) to thoroughly clean surfaces. Bleach and other cleaning solutions can also be used to remove stains, mold, and other substances that doesn't easily come off by force. Since high-velocity water spray is involved, many experts recommend that homeowners hire contractors to do the power washing instead of doing it themselves.

In general, the pressure washing process has four main components; liquid flow rate, cleaning solution, heat, and pressure. A typical power washer, however, does not include all four elements simultaneously, so you might find that there are variants without a cleaning solution feature, but has stronger pressure and flow rate, and a more efficient heater than one that allows for cleaners.

A pressure washer is composed of a gas or electric motor hooked up to a water pump, which is in turn connected to a nozzle. This is pretty much like how your water hose works – that is if your municipal water supply is capable of delivering anywhere from 750 to 30,000 psi through your tap.

There are various attachments that serve to make the pressure washer perform more efficiently. A rotating brush, for instance, cleans the metal surfaces of trucks and boats. A water broom attachment, on the other hand, breaks up the water flow into sprays that can clean driveways thoroughly.