Key Takeaways

• Selecting the wrong nozzle can cause poor performance, machine failure, or surface damage

• Two pieces of information are needed: the pump's gallons per minute (GPM) and pounds per square inch (PSI) ratings

• Orifice size determines operating pressure; smaller orifice means higher pressure, larger orifice means lower pressure

• Spray pattern degree is color-coded: smaller degrees produce more concentrated (powerful) streams

• Black nozzles are low-pressure nozzles for use with cleaning agents only

Pressure washers (also known as power washers) are a low-cost, high-impact way to make industrial cleaning faster and easier. Purchasing the wrong replacement nozzle, however, is a common and often costly mistake. The wrong nozzle can lead to poor machine performance, machine failure, or surface damage if the spray degree is too powerful for the application.

Selecting the correct nozzle does not need to be a guessing game. Two pieces of information are required to select the correct nozzle for any project.

How Do You Determine GPM and PSI for Nozzle Selection?

The gallons per minute (GPM) rating is generally found on a metal plate directly on the pump, but it can also be found in the pump's user manual. If the user manual is no longer available, refer to the manufacturer's website. Once the GPM and pounds per square inch (PSI) of the pump are known, the correct nozzle orifice size can be determined.

The orifice size of the nozzle determines the operating pressure of the machine. As a rule of thumb, the smaller the orifice, the greater the restriction of water flowing through the machine, which causes the pressure to increase.

• Choosing a nozzle with too large an orifice will reduce operating pressure.

• Choosing a nozzle with too small an orifice will limit water flow and possibly create an excessive load on the machine.

Use the reference table below to select the properly sized nozzle. Match the operating pressure (PSI) of the machine to the GPM rating.

Example: If the PSI of the pump is 2500 and the GPM is 2.8, then the nozzle orifice size needed is 3.5.

Now that the correct orifice size is determined, the next step is to select the correct spray pattern degree. Pressure washer nozzles are color-coded by spray pattern degree.

What Are You Pressure Washing?

There are five standard nozzle degrees, each coded by color. The smaller the degree, the more concentrated (powerful) the water stream. The chart below outlines the common uses of each nozzle degree. Selecting the degree that is most appropriate for the project is important; a degree that is too powerful for the application can damage surfaces. For specific questions about which spray pattern to use, consult a sales representative.

Note: Black nozzles are low-pressure nozzles and are for use with cleaning agents only.

To select the replacement nozzle, choose the correct orifice size and spray degree for the project. Continuing with the example above, if the pump has 2500 PSI and 2.8 GPM, a nozzle with a 3.5 orifice size is needed. If the project is pressure washing the bottom of a swimming pool, a green 25-degree nozzle with an orifice size of 3.5 is the correct choice.

Selecting the correct nozzle is only one factor in completing a safe and successful project. Selecting the correct hoses, spray gun, and other accessories is also critical.

Need Help Selecting Pressure Washer Accessories?

Selecting the correct nozzle for the pressure washer is one important factor in a safe and successful project. The right hoses, spray gun, and accessories are equally critical for performance and safety.

Contact us today or call us at 800-669-9650 to speak with a member of the customer service team about your pressure washer needs.

We have 11 locations across the Southeast and Midwest, including Knoxville, TN; Marietta, GA; Orlando, FL; Charlotte, NC; Little Rock, AR; Fort Worth, TX; Benton, IL; Madisonville, KY; Princeton, WV; Birmingham, AL; and Calvert City, KY.