Pressure Washer PSI and GPM: What They Mean and Why They're Important - Pressure Washer Buying Guide

Pressure Washer PSI and GPM: What They Mean and Why They're Important - Pressure Washer Buying Guide

Pressure Washer PSI and Flow Balance Scale

There are a lot of misconceptions about PSI (pounds per square inch) and GPM (gallons per minute), so we can't wait to share the following to provide you with even more knowledge if you're determining what pressure washer to buy, or what pressure and flow are right for the application you'll be using a pressure washer for.

What is pressure and flow in relation to pressure washers?

When we talk about how pressure washers work in terms of pressure and flow, we use the following descriptions to help our customers better understand what PSI and GPM mean.

  • Pressure is the measured force of water out of the end of the spray nozzle.
  • Flow is the quantity of water being delivered from the pressure washer to the cleaning area.

Both pressure and flow are important.  Finding the right balance is critical in your selection process.  

**Most inexpensive pressure washers have over-rated numbers for both pressure and flow.  Consumers buy numbers; as-in marketing encourages us that the higher the PSI and GPM for the least amount of money means we must be getting a good deal, right?!  Manufacturers use this marketing tactic to their advantage.  How do we know this?  We've spent A LOT of time testing many different manufacturers' pressure washers and have found  what is stated on a machine for PSI and GPM don't often add up.  To ensure you know exactly what kind of PSI and GPM you're investing in, use this important tip:

  • Always look for things like "MAX" in relation to pressure and flow.  Manufacturers of lower price-point pressure washers are telling you the BEST CASE scenario for their product, and possibly not the maximum pressure and maximum flow at the same time.  This makes calculating cleaning units next to impossible.  Calculating cleaning units can be accomplished by multiplying Pressure x Flow.  

Most consumer pressure washing jobs can be accomplished with 2000-3000 PSI.  An important, and often overlooked, part of a pressure washer is the flow rate or GPM.  Here's why: once debris is separated from the area being cleaned, GPM is what you'll need to rinse it away.  It works like this:

  1. PSI breaks up the debris.
  2. GPM rinses it away.
  3. Too much of one and not enough of the other reduces your cleaning efficiency.

Now that you know more about pressure washer PSI and GPM, you should be well equipped to select the right pressure washer for the job; especially if you've read through our other Pressure Washer Buying Guide articles to provide you more information.  Shop now.

Related Pressure Washer Buying Guide articles:
Choosing the Right Pressure Washer for the Job
Gas vs. Electric Pressure Washers
Hot Water vs. Cold Water Pressure Washers
Recommendations for Buying a Pressure Washer


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