Generac OneWash 3100 PSI Review

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Generac 3100 PSI8.9

The Generac 3100 PSI is a heavy-duty, gas pressure washer that is an average value based on its power and customer reviews.


The Generac OneWash 3100 PSI is a gas-powered, heavy-duty pressure washer that can be used for all your residential tasks as well as most commercial jobs. It comes with a cleaning unit count of 7440 and has multiple nozzle fittings to tackle any and every job.

This Generac model has an intricate design but is very user friendly. The Turbo and Soap Blaster nozzles make your work easier and the ergonomic PowerDial gun provides ample surface cleaning choices.

A powerful 196cc engine and a durable pump form the operational core of the machine. This Generac model is protected by a two-year warranty cover.

This detailed Generac 3100 PSI review will take you through all the necessary details about the product, from the specs to the pros and cons. Let’s get started.

Product Overview

Generac 3100 PSI Specs
Pressure 3100 PSI
Flow Rate 2.4 GPM
Cleaning Power 7440 cleaning units
Engine Power 196cc
Gas Tank 3L
Pump Type Axial cam
Weight 65 pounds
Dimensions 24.2″(D) x 18.9″(W) x 35.5″(H)
Hose Length 30 ft
Detergent Tanks 0.5 gallon
Detergent Dilution No
Water Type Cold (100°F max)



The Generac OneWash 3,100 PSI offers a max flow rate of 2.4 GPM and pressure of 3100 PSI, which translates into an impressive 7440 cleaning units. This pressure rating and the multiple nozzles will allow you to tackle anything from cleaning windows to cars and even stubborn grime on your pavements.

The gas-powered engine is powerful and capable of delivering quality cleaning power over long durations of use. Customer reviews about the performance are overwhelmingly positive.

This model delivers decent power for its price. That is why it has been rated as “average” on our rating scale.

>> Read More: Best Gas Pressure Washers


The Generac 3100 PSI pressure washer is a very well designed machine. With a combination of Generac-developed attachments and a simple and effective design, this model is user-friendly.

Generac’s PowerDial gives you the ability to easily switch across surfaces like wood, concrete, soap, and car, with equal efficiency. The Turbo nozzle enables you to clean up to 30% faster, even when the task involves stubborn grime and dirt.

It is equipped with an onboard detergent tank and a Soap Blaster attachment that dispenses soap up to 3 times farther than regular soap nozzles. This means that soaping surfaces, close or distant, has never been easier.

Weighing in at 65 pounds, this machine would be difficult to drag around the house, but luckily it comes with over-sized, “never-flat” tires that make it easy to transport.


Gas-powered and generating enough pressure for most residential and commercial uses, the Generac 3100 PSI pressure washer is a noisy machine compared to electric units. You might need to be aware of when you use it to not disturb others.

What Comes in the Box

The Generac 3100 PSI pack comes with the following parts:

  • Main Unit
  • Handle Assembly
  • High-Pressure Hose
  • Siphon Hose
  • PowerDial Spray Gun
  • Lance
  • Oil
  • Metal Hose Hook
  • Bag of Colored Nozzles
  • Spray Gun Holder
  • Soap Blaster Nozzle
  • Turbo Nozzle


The Generac OneWash 3100 PSI pressure washer comes with a 2-year manufacturer’s warranty. If anything goes wrong, you can contact Generac to get replacement parts.

📞 Phone
1-888-GENERAC or 1-888-436-3722
📨 Mail
Generac Power Systems, Inc., S45 W29290 Hwy. 59, Waukesha, WI 5318


8.9Expert Score
Generac OneWash 3100 PSI Review
Generac 3100 PSI Pressure Washer Review
The Generac 3100 PSI is a heavy-duty, gas pressure washer that is an average value based on its power and customer reviews.
Generac 3100 PSI
  • 𝗚𝗿𝗲𝗮𝘁 𝗰𝘂𝘀𝘁𝗼𝗺𝗲𝗿 𝗿𝗲𝘃𝗶𝗲𝘄𝘀. The Generac OneWash 3100 PSI has great customer reviews with the majority of customers being very satisfied.
  • 𝗛𝗶𝗴𝗵 𝗽𝗼𝘄𝗲𝗿. The Generac 3100 PSI delivers a cleaning unit count of 7440. This is enough for most residential tasks and commercial use too.
  • 𝗢𝘃𝗲𝗿𝘀𝗶𝘇𝗲𝗱 “𝗻𝗲𝘃𝗲𝗿-𝗳𝗹𝗮𝘁” 𝘁𝗶𝗿𝗲𝘀. This machine rests on large tires that help maintain its balance and maneuverability across all terrains.
  • 𝗢𝗻-𝗯𝗼𝗮𝗿𝗱 𝗱𝗲𝘁𝗲𝗿𝗴𝗲𝗻𝘁 𝘁𝗮𝗻𝗸. The Generac 3100 PSI model has an “easy to operate”, 0.5-gallon detergent tank to simplify the soaping process for you.
  • 𝗠𝘂𝗹𝘁𝗶𝗽𝗹𝗲 𝗰𝗹𝗲𝗮𝗻𝗶𝗻𝗴 𝗮𝘁𝘁𝗮𝗰𝗵𝗺𝗲𝗻𝘁𝘀. Along with the four different general use nozzles, Generac also offers a high-pressure nozzle that cleans 30% faster. The Soap Blaster nozzle provided helps you apply soap up to 3X farther.
  • 𝗘𝗿𝗴𝗼𝗻𝗼𝗺𝗶𝗰 𝗣𝗼𝘄𝗲𝗿𝗗𝗶𝗮𝗹 𝘀𝗽𝗿𝗮𝘆 𝗴𝘂𝗻. Generac’s unique PowerDial spray gun gives the user an option to switch between multiple pressure settings. Just rotate the dial to choose any among the wood, concrete, soap, and car pressure settings.
  • 𝗗𝘂𝗿𝗮𝗯𝗹𝗲 𝗽𝘂𝗺𝗽 𝗮𝘁 𝗶𝘁𝘀 𝗰𝗼𝗿𝗲. This pressure washer is built on the more durable brass head axial cam pump, adding to the machine’s longevity.
  • 𝗛𝗲𝗮𝘃𝘆 𝗺𝗮𝗰𝗵𝗶𝗻𝗲. At 65 lbs, the Generac 3100 is a heavy machine and requires more effort to drag around the house and yard.
  • 𝗢𝗽𝗲𝗿𝗮𝘁𝗶𝗼𝗻 𝗮𝗻𝗱 𝗺𝗮𝗶𝗻𝘁𝗲𝗻𝗮𝗻𝗰𝗲 𝗰𝗼𝘀𝘁. Gas-powered pressure washers require regular maintenance and this model is no different. Operational costs, like fuel, are also involved.
  • 𝗠𝗲𝘀𝘀𝘆 𝘁𝗼 𝗼𝗽𝗲𝗿𝗮𝘁𝗲 𝗮𝗻𝗱 𝗿𝗲𝗹𝗲𝗮𝘀𝗲𝘀 𝗳𝘂𝗺𝗲𝘀. Customers have often found the product to be leaky. This creates messes that are difficult to manage. Since it’s gas-powered, the machine also releases fumes that can be difficult to bear.
  • 𝗧𝗵𝗲 𝗲𝗻𝗴𝗶𝗻𝗲 𝗰𝗮𝗻 𝗴𝗲𝘁 𝗷𝗮𝗺𝗺𝗲𝗱. Some customers found that the engine refused to start after even a short storage period.


A quick assembly process will help you set up this machine in no time. You can watch an assembly video by clicking on this link.

Generac OneWash 3100 PSI

You can also follow the steps outlined below and set the machine up at home.

Steps required for assembly:

  1. Start by attaching the handle assembly to the handle support. Align the handle and the support, push the latch buttons on the support and start sliding the handle down. The buttons will lock the handle assembly into place.
  2. Now, install the metal hook in the space given at the back of the handle assembly. You can simply slide the hook into position and coil your high-pressure hose around it when it is not in use.
  3. Set the four colored nozzles in place by following the placements given at the front of your handle assembly.
  4. Use the clips given in the pack to attach the spray gun holder, to the back of the handle assembly on the right side of the machine. Align the holder to the holes on the handle and use the clips to secure it in place.
  5. Next, it’s time to prepare the spray gun. Attach the metal lance to the trigger gun by inserting it into the gun and then secure it by turning the connector clockwise until it is tightly fastened.
  6. Connect the siphon tube to the machine and the on-board detergent tank. You can do this in two simple steps:
    1. Attach one end to the machine by pushing it into the opening provided at the top of the high-pressure hose outlet.
    2. Attach the other end into the opening provided on the lid of the detergent tank.
  7. Fill the engine oil tank on the left side of the machine with the recommended engine oil(you will receive a small pack of engine oil within the package too). Once done, ensure that the lid is properly secured.
  8. Next, open the lid on top of the black color fuel tank. Fill this tank with the recommended fuel. Here are some pointers about this step:
    1. Use clean, fresh, unleaded gasoline.
    2. Minimum rating of 87 octane/87 AKI (91
    3. RON).
    4. Up to 10% ethanol (gasohol) is acceptable.
    5. DO NOT use E85.
    6. DO NOT use a gas oil mix.
  9. Now you can connect the high-pressure hose to the water outlet and the trigger gun.
    1. Take one end of the high-pressure hose and attach it to the upper outlet at the back of the machine. Press the hose into the outlet and turn it clockwise until the connection is secure.
    2. Now connect the free end of the high-pressure hose to the opening at the bottom of the gun. You can do this by inserting the hose into this opening and turning it clockwise until the connection is secure.
  10. Finally, attach the garden hose to the inlet just below the high-pressure hose outlet at the back of the machine. Press the garden hose into the opening until the connection is secure. Connect the other end to your water supply.

With this final step, your pressure washer is all set up.


Once the assembly process is completed, ensure that all the connections are secure. After the check is successfully completed, flip the switch at the front of the machine to “on”.

Pull the recoil gently at first. Once there is some resistance, switch to pulling the recoil forcefully.  After the pressure washer is running, squeeze the trigger for about 30 seconds to release all air pressure.

Generac provides you with a number of nozzle fittings that can help you fulfill the household or commercial task you are about to take on. Here is a guide that will ensure you use the correct fittings.

  • Turbo (0°) Nozzle: High pressure, swerving throw. Helps remove stubborn grime and dirt 30% faster than regular nozzles.
  • Red (0°) Nozzle: Very high pressure, low flow. To clean surfaces like unpainted metal or concrete.
  • Green(25°) Nozzle: Lower pressure, high flow. Ideal for use on sidewalks, lawn furniture, concrete, and brick surfaces
  • White (40°) Nozzle: Medium pressure, medium flow. To clean wood, painted brick, and stucco, vinyl, painted siding.
  • Black (Soap) Nozzle: Soap nozzle. For applying soap and detergent.
  • Soap Blaster (Soap) Nozzle: Soap nozzle with up to 3 times farther reach. Allows you to apply soap and detergent on surfaces that may be out of your reach.

To use the detergent tank, start by filling the tank with a detergent solution. Ensure that the solution used is suitable for pressure washers and prepare the solution as required by the detergent label.

Now you need to check if the siphon hose is connected securely. Finally, attach either the soap nozzle or the Soap Blaster nozzle, and you are good to go.

Verdict on the Generac 3100 PSI

The Generac 3100 PSI is a powerful and user-friendly design. It is easy to assemble and is suitable for residential and commercial jobs. When compared to other gas-powered pressure washers, it is moderately priced and includes a decent two-year warranty cover.

If you are looking for a reasonably-priced, heavy-duty, gas-powered pressure washer, this is an option worth considering.


Additional information

Specification: Generac OneWash 3100 PSI Review

Type Gas
PSI 3100
GPM 2.4
Cleaning Units 7440
Duty Heavy
Water Cold (100* F Max)
Engine Horizontal-shaft engine
Gas tank 3 L
Electric Start Yes
Pump Axial cam
Dimensions 24.2"(D) x 18.9"(W) x 35.5"(H)
Weight 65 lbs
Hose Length 30 ft
Detergent Tank 0.5 Gallon
Nozzles 0°, 25°, 40° & Soap
Accessories Ergonomic spray gun, Convenient on-board 1/2 gallon detergent tank for hassle free cleaning
Onboard Storage Onboard storage for cleaning detergents
Warranty 2 years


Videos: Generac OneWash 3100 PSI Review

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