Pressure Washer Psi Guide

Northstar , Comet, Briggs and Stratton & More

Pressure washer PSI is an important consideration whenever you think about shopping for a pressure washer unit for doing a certain cleaning project and would like to know which one to go for. The entire pressure washer industry in North America uses PSI which stands for pounds per square inch to classify pressure washers. In Europe and other countries this same pressure output is measured in bars.

Dewalt Pressure Washer High PSIAlso important when dealing with pressure washers apart from PSI is what is known as GPM. This is gallons per minute that a pressure washer releases. It is determined by the pressure washer pump and engine or motor. Electric cold water pressure washers often use a motor to run the pump. Gas powered pressure washers use a more powerful gasoline powered engine to deliver more power to the pump for a higher GPM.

The combination between PSI and GPM is an extremely important consideration when considering any given pressure washer. The higher the two figures the more power and effectiveness that can be expected in any cleaning projects. It follows that electric pressure washers of say 1500psi or 1600psi pressure output have lesser GPM flow rate because they use a less powerful motor to drive the pump.

It is when pressure washer psi is considered when manufacturers and the industry at large is able to classify pressure washers. This informs the price of the pressure washer as well as its application in terms of cleaning projects that it can do. There are three mainly used classifications of pressure washers based on PSI namely light duty, medium duty and heavy duty washer units.

Light Duty Pressure Washers - 1500-2100 PSI

These are typically home pressure washers. It is in this category that we find some of the best pressure washers for home use. They are almost all electric cold water washers and have a GPM of between 1.5 and 2.0 GPM. Pressure washer models in this category can do smaller projects such as the following;

  • Grill
  • Patio Furniture
  • Fencing
  • Car
  • Siding
  • Garage Door
  • Driveway (higher end)
  • Paint Prep (higher end)
  • Oil Stains (higher end)
  • Stairs
  • Walkway

As hinted above light duty washers with the stated pressure washer psi may struggle with some cleaning jobs. Even though they might do them it will take longer than is necessary and might also require the use of detergents. This can become costly overall than purchasing a higher pressure washer psi output unit. Some jobs listed above will be better completed by a light duty pressure washer of 2100 psi and 2.0 GPM.

Medium Duty Pressure Washers - 2150-2800 PSI

Pressure washer psi of units in this category is significantly higher than that of light duty washers above. They also have greater water flow rates of between 2.1-2.7GPM. They can do a bit more challenging jobs at this power output expressed in the combination of PSI and GPM. Most pressure washers in this class are electric pressure washers. In fact some of our best electric pressure washers reviewed within this site are found in this class. They do the following jobs very efficiently;

  • Garage Door
  • Driveway
  • Oil Stains
  • Deck
  • Patio
  • Stairs
  • Walkway

In as much as pressure washers in this category can do your vehicle, some patio furniture and some types of wood fencing this has to be under controlled conditions. This is achieved by properly setting your pressure output at the correct level. Higher psi pressure washer units can easily damage delicate surfaces and items.

Heavy Duty Pressure Washers - 2850-4000 PSI

Pressure washer psi for units in this class is advanced by industry standards. This also includes the water flow rate which ranges between 2.8GPM to 5.0GPM. It is also possible to find pressure washers that are as much as 5000 psi in pressure output in this category. These are the ones that are used for professional and commercial projects at construction sites, farms, industrial sites and so on.

As one can guess, heavy duty pressure washers are gas powered. Some of them are even heated pressure washers meaning they are hot water pressure washers. Heavy duty pressure washers can run for hours without stopping something that light duty and medium duty washers cannot achieve. They even have onboard water tanks for jobs offsite in remote areas where water supply by hose could be unavailable. These are self contained high pressure washers.

Also important to note is that units with high pressure washer psi such as these involve increased maintenance work such as changing pressure washer pump oil on a regular basis and also getting the washer engine serviced. Examples of pressure washers brands in this class include Briggs & Stratton, Northstar, Comet, Craftsman, Campbell Hausfeld, BE and Simpson amongst others.

In considering the three classes of pressure washers based on their respective power output, it is apparent that lower PSI washers will take longer to do certain jobs which can easily be accomplished within a shorter period of time by higher powered washers.

For example, on average a light duty washer can take 10 minutes to clean a surface 10.4 sq ft the same amount of time taken by a heavy duty pressure washer to finish cleaning a 100.210 sq ft area. That's nearly 10 times faster than a light duty washer.

Pressure Washer PSI and Attachments And Accessories

Pressure Washer Turbo NozzleHow much your identified pressure washer psi amounts to matters when it comes to considering the different attachments and accessories that can also go with your pressure washer. Each manufacturer has its own accessories, parts and attachments. For example Karcher pressure washer accessories and parts are made by Karcher. These are to a big extent defined by the output of your washer measured in PSI when considering their use.

Pressure washer nozzles, guns, wands, telescopic wands and so on are usually made for certain outputs. This makes it important to select a pressure washer that will have a wide range of after purchase accessories.

Such units are also often highly priced. Most pressure washers in the light duty class come with a vario spray wand. They do not use quick connect spray tips nor turbo nozzles that help the machine deal with tougher dirt.