Login to Your
My Simpson Account
Sign up / Register your product here

eighteen + eighteen =

Frequently Asked Questions

A: There are three questions you should ask yourself when determining what kind of pressure washer is right for you.

The first question is “Where do I intend to use the pressure washer? At home or at work?” Typically, you don’t need as powerful of a pressure washer for your personal use at home as you might on a job site. Household jobs for example, shouldn’t need a machine larger than 3000 PSI, whereas 3100 PSI would be minimal for job site usage.

Another helpful question to ask yourself is, “What do I want to clean?” If you are expecting to use your pressure washer for basic household jobs such as driveways, decks, patio furniture, etc. you can get by with a unit that offers relatively low pressure. If your plans are a little bit more daring such as blasting mold or mildew off of concrete or prepping the house for painting you should consider a unit with higher pressure.

Lastly, how much cleaning will you be doing? Will you be cleaning large surface spaces? If the answer is yes, you should consider a unit offering a higher GPM. More water means more cleaning power! A higher GPM will get the job done quicker.

A: The choice of a pressure washer comes down to the type of cleaning you would like to perform and the frequency of using the unit will see. For smaller jobs or when you may only use the washer once or twice a year, an electric-powered pressure washer may be for you. For larger jobs, more frequent use, and the ability to pressure wash untethered or on job sites without electric power, a gas-powered pressure washer will work best.

A: There are up to five different quick connect nozzle spray tips; four high pressure and one low pressure “Soap” nozzle. The operator can select a high pressure nozzle spray pattern which best suits the cleaning application. Note: Cleaning solutions cannot be applied with high pressure spray tips (Red, Yellow, Green or White).

RED Nozzle @ 0°
Provides a concentrated spot of high pressure water allowing you to be further from the surface being cleaned and to blast off stubborn material. USE CAUTION with this nozzle as the force available will actually penetrate soft materials or surfaces. Use for reaching high areas such as under eaves or cleaning tar, chewing gum, etc. from sidewalks. This nozzle is useful for breaking up large areas of loose paint to strip a surface. This nozzle can assist in moving excess mortar from brick construction and rust flakes from steel.

YELLOW Nozzle @ 15°
Provides a narrow fan of concentrated water pressure for removing paint, mildew, etc. By testing several angles between the spray and the surface being worked, the best angle may quickly be identified. The yellow nozzle is also used to remove loose paint from wood, masonry, metal, etc. You will be able to remove heavy oxidation, mildew and marine growth from boats or clean heavy equipment.

GREEN Nozzle @ 25°
Provides a wider fan for pressure cleaning and rinsing. Used for removing mildew, light to medium oxidation and dirt from aluminum siding, rinsing stripped areas or general light cleaning in preparation for painting.

WHITE Nozzle @ 40°
Provides a wide fan for cleaning and rinsing. This nozzle is used for general wash-down, light cleaning, rinsing off chemicals used in building restoration and sweeping driveways or parking areas.

BLACK Soap Nozzle
A low pressure nozzle used to apply cleaning solutions. Note: Cleaning solutions cannot be applied with high pressure spray tips (Red, Yellow, Green or White)

A: The answer is both. PSI and GPM work together and the right combination is important depending on your pressure washing needs.

PSI stands for “Pounds per Square Inch” and refers to the amount of pressure that the respective machine can produce.
GPM stands for “Gallons per Minute” and refers to the amount of water coming from the unit.
To clean productively, a pressure washer should be doing two things: stripping or scrubbing and rinsing. This is what sets a pressure washer apart from a regular garden hose.

PSI exerts the pressure to “strip” or scrub off the dirt while GPM is the rinsing power that washes the dirt away.
The combination of PSI and GPM results in “Cleaning Units” or CU. This is a way for you to measure the overall performance of the machine and compare efficiency of one to another. Cleaning units is calculated by multiplying PSI and GPM.


  • A pressure washer with 3000 PSI and 2.0 GPM has 6000 Cleaning Units.
  • A pressure washer with 2700 PSI and 3.0 GPM has 8100 Cleaning Units.

This example points out an important fact. Higher PSI does not mean it’s necessarily “better.” GPM is usually more important to a commercial user because chemicals are typically involved when the machine is intended for professional purposes. Since the chemicals are working to break up the grime, the flow (GPM) is more important because it is needed to rinse the debris away quickly. It all depends on the task at hand.

For more information, refer to “How do I select the right pressure washer for me?”

A: For water usage, yes, it is. Most residential pressure washers use between 1.2 and 2.5 gallons per minute (GPM). Flowing at 5-GPM, an openly running garden hose uses 2-5 times more water than most residential pressure washers. And because residential pressure washers produce water pressures between 2300-3500 pounds per square inch (PSI) of dirt-blasting power, versus the 20 PSI produced by a typical garden hose, using a pressure washer greatly reduces the time you will need to run the water when cleaning your car, boat, siding, or anything else.

A: Maintenance-free pumps contain long-wear components submerged in a high-grade synthetic oil designed to last the life of the pump. Since the pump does not require regular oil changes, they are called maintenance-free. Note: winterizing your maintenance-free pump is still necessary.

A: If you see water spraying from a valve on your pressure washer pump it is most likely coming from the thermal relief valve (TRV). Most pressure washer pumps are equipped with a thermal relief valve (TRV) to protect the pump if the water inside gets too hot. The water inside your pump can get too hot if you leave the pump running for too long without using the spray gun to pressure wash, or by allowing hot water to enter the pump from a garden hose that has been in the sun. To prevent the water inside the pump from getting too hot and opening the TRV, only use cold water in your pressure washer, turn off the machine if you will not be using the spray gun for more than two minutes, and keep the supply hose out of direct sunlight.

A: No, you must apply soap with the black, low-pressure nozzle. High-pressure nozzles will not allow the soap injection valve to open. Once the soap is applied then you can switch to a higher pressure nozzle to clean and rinse the surface.


A: If your pressure washer has soap injection capability but is not fitted with a soap tank, there should be a barbed fitting for a soap injection siphon hose located near the high-pressure hose connector. Gently slip the siphon hose onto the barbed fitting and place the filter end into the soap container/bucket. Only use cleaning agents approved for use with pressure washers. DO NOT USE BLEACH.


A: Only detergents that are listed by the chemical manufacturer to be designed and safe for use in pressure washers, specifically, all-purpose detergent and non-caustic detergent.

A: The nozzle is what creates the pressure and also the spray pattern of your pressure washer. If you have the incorrect nozzle you may not get the full potential out of the machine. Always make sure that your pressure washer nozzle is clean and free of debris.

A: Yes. Use the white, 40o nozzle and keep a good distance from the window.  However, before you pressure wash, you should inspect the window frame for cracked calking / glazing, peeling paint, and areas where water may leak inside the house before you use the pressure washer.  Correct these issues before you pressure wash the windows.

A: OHV means overhead valve. OHV pertains to the engines created for pressure washers.

A: Belt driven pressure washers are generally for commercial use because a belt driven pump is ideal for cleaning applications that are over 20 hours per week. On a belt drive unit, the high pressure pump has less RPM than a direct drive, reducing heat and vibration, which in turn minimizes internal wear and tear.

If you are using your pressure washer less than 20 hours per week, you may be better suited for a direct drive machine. These machines are typically more cost effective, lighter in comparison and easier to transport.

A: A limited warranty means that there are limitations to what is covered and under what conditions the warranty would not apply as stated in the Limited Warranty for each product.

A: click here to learn more