Is PSI or GPM more important to consider?
The answer is both.
PSI and GPM work together and the right combination is important depending on your pressure washing needs.
PSI stands for “Pounds per Square Inch” and refers to the amount of pressure that the machine can produce.
GPM stands for “Gallons per Minute” and refers to the amount of water coming from the machine.
To clean productively, a pressure washer should be doing two things: stripping or scrubbing and rinsing. This is what sets a pressure washer apart from a regular garden hose.
PSI exerts the pressure to “strip” or scrub off the dirt while GPM is the rinsing power that washes the dirt away. It is the combination of PSI and GPM that delivers the results.
GPM is usually more important to a commercial user because chemicals are typically involved when the machine is intended for professional purposes. Since the chemicals are working to break up the grime, the flow (GPM) is more important because it is needed to rinse the debris away quickly. It all depends on the task at hand.