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Pressure Washer FAQs

Pressure Washer FAQs

  • What is a power washer?

    A power washer is an outdoor power tool that makes cleaning easier by using a high-pressure spray of water to clean a surface. A gasoline engine or electric motor drives a pump, which is supplied by your home’s water supply. The water enters the pump at about 50 PSI, is compressed (and thus pressurized) inside the pump, and exits the pump at as much as several thousand PSI, depending upon the unit. This high-pressure water travels through a hose to a spray gun. The nozzle at the end of the spray gun directs the high-pressure spray as you clean.

    The force of the high-pressure spray loosens dirt and flushes it away. On more professional-grade models, the spray is even powerful enough to strip paint, which is useful in paint preparation. You can use many detergents with a power washer, too, for even more effective cleaning. And there are accessories you can buy that make cleaning even easier.

  • What is “PSI” and “GPM,” and why are they important?

    PSI is short for “pounds per square inch.” It is a measure of the water pressure coming out of the power washer. A typical garden hose dispenses water at about 50 PSI, and a coin-operated car wash provides about 700 PSI. A power washer, by contrast, typically dispenses water at several thousand PSI, depending upon the model.

    GPM stands for “gallons per minute,” and describes how much water is flowing through the power washer.

    You’ll find both of these ratings on a power washer, because they’re both important. Together, they provide your power washer’s cleaning power. PSI provides the “oomph” you need to lift dirt and grime, and GPM provides the necessary quantity of water to wash it away.

    The real measure of a power washer’s cleaning power can be found by multiplying PSI by GPM. The higher the number, the greater the cleaning power. For example, a garden hose delivering water at 50 PSI and 5 GPM has a cleaning power of only 250. A power washer, however, delivering water at 2500 PSI and 2.3 GPM has a cleaning power of 5750.

  • How do I select the right power washer?

    The first question you should ask yourself is where you intend to use the power washer—at home or at work. A power washer used primarily at home probably doesn’t need to be as powerful as one that is used on a job site. Around the house, for example, you shouldn’t need more than 3000 PSI. To be fully productive on the job site, though, you probably need at least 3000 PSI.

    Next, ask what you want to clean. If you’re looking to simply take the dirt and grime off the driveway or patio furniture, you can use a unit with a relatively low pressure—perhaps 2500 PSI. If, however, you plan on scrubbing mold and mildew off concrete, or prepping a house for painting, you should consider a unit with a higher pressure.

    Finally, think about how much cleaning you will be doing. If you’re cleaning a number of items, or if you need to clean a large area, you might want to consider a unit with a higher GPM. More water means more cleaning power, and a higher GPM will make the job go faster.

  • Why Generac power washers? Isn’t Generac a generator company?

    You’re right—Generac’s primary focus has been designing and manufacturing generators for residential, commercial and industrial applications.

    Nonetheless, back in the early 1990s, we applied our knowledge of air-cooled engines and portable product design to power washers—it was a natural evolution. And for the first time power washers were readily available to consumers at a price they could afford. Along the way, we were granted several patents that have since changed the industry.

  • How often does a power washer require maintenance?

    All power wasers require periodic maintenance, such as oil and air filter changes, to ensure maximum performance for years of reliable service. Refer to the owner's manual for routine maintenance procedures and schedules. 

  • What type of oil should I use?

    An SAE rated high detergent oil means that API Service Class SF requirements for gasoline engines, similar to your car. Refer to your owner's manual for details. To find your owner's manual online, visit our Product Support page and enter your serial number or model number. 

  • How do I store this unit for the winter?

    Long term storage is important, espcially in the winter. It is highly recommended to use Pump Saver to winterize the pump, which prevents damage internally due to freezing water. Full long term storage instructions are included in the unit's manual. To find your manual online, visit our Product Support page and enter your serial number or model number. 

  • Can I use hot water?

    No, water must be no more than 100°F. Hot water can cause permanent damage to the pump. 

  • Can I use bleach?

    No, bleach can cause permanent damage to the pump, hose, gun and nozzles. Use only power washer soap as a cleaning agent. 

  • Can I connect my power washer to one of your water pumps?

    No, the power washers require a steady source of clean, pressurized water, such as the hose spigot on your home. We do not suggest this, as the water pump is dependent on another source of standing water, which may contain particulates that could damage the power washer, or not enough water to properly supply the power washer.

  • Can I connect this to my rain collection bin or retention pond?

    No, the power washers require a steady source of clean, pressurized water, such as the hose spigot on your home. It needs a minimum of 3.8 gallons per minute.

  • How do I know which nozzle to use?

    The nozzles that come standard with the power washer all have different spray patterns and intensities. We recommend starting with the lowest pressure nozzle first, and test it in an area for results first. Nozzles that have a higher pressure or tighter spray pattern can easily cause damage to softer surfaces. The description for the nozzles that came with your power washer are in your owner’s manual. Owner’s manuals and other documentation can be downloaded from our Product Support Page using the unit’s serial number, or contact us for further assistance.

  • I no longer have my Owner's Manual, how can I get another copy?

    Owner's manuals and other documentation can be downloaded from our Product Support Page using the unit's serial number, or contact us for further assitance. 

  • If I have a problem with my power washer where do I go for help?

    Any Authorized Generac dealer can perform warranty service. To find your local authorized Generac dealer see our locator or contact us for additional information. Our Authorized Service Centers provide parts, service and information on Generac equipment, regardless of where it was purchased. Authorized Service Centers are staffed with trained technicians certified in supporting all aspects of the Generac power washer line.

Online Product Support

Looking for more? In Generac's Online Product Support section you can find the specifications, product manuals, frequently asked questions, how-to videos, and more for your product. Enter your model or serial number to go directly to your specific information or find your model through the Product Lookup.