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The Lawn Review: Home » Pressure Washer GPM vs PSI: Explained (2023)

Pressure Washer GPM vs PSI: Explained (2023)

PSI and GPM are two acronyms to know when it comes to buying a new pressure washer. Both are often used to express the power of the pressure washer, but as I found out the hard way, are very different measurements. 

testing lawn tools

A good pressure washer is an indispensable tool for your home, yard, and property. But, choosing the right machine for your needs can be a little confusing. That’s especially true when you’re faced with terms you may not be familiar with.

For example, every pressure washer you look at will have a GPM and PSI rating. These are specifications that determine your pressure washer’s power and capabilities. Understanding these two specs and how they affect your pressure washer’s performance is a key to success.

What Do GPM and PSI Mean on a Pressure Washer?

Pressure washers are designed to create a strong, steady stream of water for washing and cleaning. Both GPM and PSI are important factors to consider when buying and using one. Here’s a quick rundown of what each is and how they affect your power washer’s performance.

What Is GPM on a pressure washer?

Gallons Per Minute, or GPM is the volume of water that leaves your pressure washer. Generally, GPM ratings will range anywhere from 1.2 gallons per minute to 4 gallons per minute. If you’re a novice, or will only use your pressure washer occasionally for light cleaning, opt for a lower GPM to begin with. Higher GPM is more suitable for heavy-duty cleaning.

pressure washer nozzle

The higher the GPM, the more water that flows, meaning your cleaning jobs will go quicker because the water spreads farther. However, a lot of water over a large surface doesn’t have much cleaning power. For that, you need a higher PSI.

Gas pressure washers tend to have higher PSI and GPM than electric pressure washers.

What Is PSI on a Pressure Washer?

PSI, or pound-force per square inch, is the amount of cleaning pressure your machine is capable of producing. It’s the force of the water as it is pushed through the nozzle. You can adjust the PSI to ensure a proper cleaning and to avoid damage. For example, a high PSI but a low GPM, will produce a high amount of pressure over a fairly small area.

greenworks 3000 psi pressure washer

Which Is More Important, PSI or GPM on a pressure washer?

PSI and GPM work hand in hand. Having a high PSI means you have a laser beam of power. The range in GPM tells you how wide the laser beam will be. So high PSI and low GPM means a super small beam. High PSI and high GPM means a big freaking cannon of water.

high PSI

As you can see, both of these are important in order to achieve the maximum cleaning capacity of your pressure washer. Choose a pressure washer with a high enough PSI and GPM to accomplish your cleaning goals. However, stay away from commercial pressure washers with a high PSI. This type of pressure washer will be tougher to operate due to the increased force of the water. An inexperienced user may find it to be very physically demanding, if not impossible to use safely and effectively.

A lot of these you won’t have to worry about accidentally buying because they are so darn expensive. I’d stick with a nice electric pressure washer that is incapable of getting out of hand.

What Are the Best PSI and GPM Settings?

When choosing a new power washer, you’ll want to look for one that provides enough power to achieve your goals. If you have fairly light duty cleaning you want to do occasionally, opt for a lower powered model. Big jobs to tackle? Choose a pressure washer with a higher GPM and PSI rating to get the job done fast and effectively.

greenworks electric pressure washer

No matter what you’re using your pressure washer for, or what its settings are, make sure you work safely. Wear safety goggles and other protective equipment and keep children and pets away from the machine.

 Why we review lawn tools

The reason we started this website in the first place was because we had so much trouble trying to find reasonable, understandable, honest reviews for lawn equipment. And it’s not cheap! After hours and hours of research, trying products and returning them, and messing up our yards – we started this site. 

toro mower battery recycler

As people who had to learn the hard way, we want you to know exactly what you are signing up for before you purchase a piece of equipment. That’s why we are committed to providing honest, easy-to-understand reviews that mean something. 

What features to look for in a pressure washer

Honda pressure washers make it relatively easy to knock off one of the biggest must-haves on your list: a reliable and powerful engine. But there are a few other things we recommend truly making sure are available when searching for a new pressure washer.

If you’re going electric – make sure to check out our ultimate guide to electric pressure washers.

Nozzles Matter

  • When choosing a pressure washer, you should pay attention to the nozzles included in the package. Two types of spray nozzles are available, adjustable spray nozzles that can be controlled and quick-connect nozzles with predefined spray patterns.  
  • The predefined spray patterns typically come in different angles, allowing for you to quickly switch between a broad, lower pressure spray or a narrow, higher pressure stream.
  • Quick connect nozzles are super convenient, but they’re almost like airpods – you can lose them!

Soap tank availability

  • Additionally, you may want to consider a soap tank-equipped pressure washer. Some of these pressure washers have “foam cannons” where you can simply add some soap and it will mix it in with the water. Pretty cool.
  • I recommend a soap tank for cars and windows.
soap canisters

Wheels on pressure washers

  • Despite these seemingly minor features, they can have a big impact, especially with larger units. No sense in lugging around one of these in your yard and tripping all over the place.
  • Some pressure washers have a tendency to flip over and be top heavy, so make sure the base is sturdy.
  • If you’re on the job site, keep an eye out for never-flat tires that will protect the wheels in case there are spare nails laying around.

Hose types

  • There’s a big difference between how easy or difficult it is to use a pressure washer based on the kind of hose that comes with it. Stiff, rigid hoses make it extremely difficult to have any maneuverability without messing up the job or knocking over the base.
  • Length is also important for pressure washer hoses as you can end up in a tight spot, literally, if you don’t have enough reach.

Alex K

Alex is a lawn tool enthusiast who cut his teeth as a normal Joe lawn dad. After burning through expensive, fancy tools, Alex became dedicated to finding the best tools on the planet. He is now a leading expert on electric lawn tools, quoted in the Washington Post among other publications.