A premium pressure washer that combines excellent performance with durable build quality for long-lasting value.

Product Description

When you need a power washer that delivers top performance and can stand up to daily use, choose the STIHL RB 400 DIRT BOSS® pressure washer. It features a powerful 196 cc (6.5 hp) engine that can output 2,700 psi of water pressure at 2.7 gallons per minute. It also features the durability STIHL products are known for, with a brass manifold pump design, stainless steel valves and ceramic-coated pistons. There is also a cast-iron engine liner and a built-in shutdown feature when the oil level is low. The RB 400 DIRT BOSS® also features an easy start pump system and convenient detergent injector system. And with its 25' no-kink flex hose, you can clean more area without having to move the machine. Finally, the pressure washer uses a wide range of optional cleaning accessories, including rotary surface cleaner, water broom, nozzle options, hose extensions, a gutter cleaner, aluminum wand extension, pivot coupler and official STIHL cleaning agents. When you need to demolish dirt on a daily basis, the DIRT BOSS® handles the pressure with ease.

Model Features

  • View the RB 400 features.
  • 2-Piece Lance & Gun Assembly
    This pressure washer features an easy, convenient 2-piece lance and gun assembly. The lance design is also extended for better accuracy in tall applications.
  • Anti-Vibration System
    This pressure washer features a STIHL-engineered 4-point vibration isolation system. This reduces pump vibration during use for increased unit longevity.
  • Automatic Fuel Shut-Off Valve
    This pressure washer features a combined on/off and fuel valve control. This allows the user to shut unit off and close fuel valve automatically for easy, no-mess transport.
  • Easy Start Pump System
    The Easy Start Pump System features a pressure relief valve, allowing users to start the unit without any back pressure from the pump. It enables quick, easy starting with no hard cord pulls.
  • Easy-Access Inlet & Outlet Water Connections
    Both inlet (water coming into the pump) and outlet (water going from the pump to the gun) connections are easy to access for faster setup
  • Stainless Steel High Pressure & Brass Detergent Nozzles
    This pressure washer includes stainless steel nozzles for use with high-pressure water and a brass nozzle for use with detergent. These premium nozzles are designed to resist corrosion and wear.


196 cc 12.0 cu. in.)
3.6 L (3.8 qt.)
620 L/h (2.7 gpm)
2,700 psi
41 kg (90 lbs)
724 x 699 x 654 mm (28.5 x 27.5 x 25.75")
724 x 699 x 1003 mm (28.5 x 27.5 x 39.5")

Important Information

WARNING! Improper use of any power tool may cause serious or fatal injury. Read, understand and follow carefully the operating and safety instructions in your instruction manual before using such products.

STIHL products sold through U.S. STIHL Dealers are for distribution in the United States only.


RB 400 DIRT BOSS® is rated 4.5 out of 5 by 51.
Rated 3 out of 5 by from Pump leaked oil in 2 hours of first use Bought this unit being an fan/owner of several of Stihl’s other products. Paid a little more than some similar spec’d models, but wanted a quality unit. I had an oil leak in the first 2 hours of use. I believe the leak came from the pump. My dealer replaced the unit, but I’m left with concerns for the long term durability of the pressure washer. I don’t put a lot of use on the washer and am concerned about another failure just out of warranty. My experience, as well as other reviews don’t inspire confidence that one expects with a premium priced product. Especially a Stihl product.
Date published: 2019-08-19
Rated 2 out of 5 by from Pump went out after about 25 hours. Pump went out after approx 25 hrs of use. Machine is leaking from pump and now wont even stay running.
Date published: 2019-08-01
Rated 4 out of 5 by from Expensive but good I bought this product a few weeks ago. So far, it's done everything I needed. I wash my truck with it, first using a foam cannon, then switching to a 25 degree fan tip. I washed all my outdoor furniture with it, and got great results. I also purchased the rotary cleaner to wash my driveway, porch, and back decks. It was excellent for all of these. The rotary head makes quick work out of flat surfaces, getting the job done in half the time. The machine cranks on the first pull most times, never needing more than 2 or 3 pulls. The power is consistent, no back firing, the engine runs smooth and is quieter than others I've used. It's not as powerful as other pressure washers on the market at the same price point but is powerful enough for my needs. The 2.7 gpm seems to make a big difference in terms of cleaning power. That said, I have two negative things to say about this machine: it's expensive, and it's cumbersome. I was willing to pay the price for Stihl's name. This is my 5th piece of Stihl equipment, and I will always look to them first when purchasing a new piece of equipment. But it does hurt to fork out that much for a pressure washer to be used around the house. As far as it being cumbersome, it is very wide, making it extremely difficult to use on stairs. This could be helped with a longer hose, but after spending $$$ on the pressure washer and $$$ on the rotary cleaner, I just was not willing to spend any more. I'm counting on this product to last a long time. That is why I spent the $$$ on it. To anyone in the market, I can say that this machine will do the job around your home. If you plan on washing driveways and sidewalks, the rotary tool is a must. You can also use the rotary on wood surfaces, but it did remove some of the stain from my deck.
Date published: 2019-07-29
Rated 5 out of 5 by from Beyond Expectations What else is there to say? This machine is way beyond expectations. I had an electric power washer for the cars and tried it on the fence, worked okay but needed more power…so after researching I chose the Stihl Dirt Boss. I have a weed whacker from Stihl, blower, chainsaw and a lawn edger...now I have a Dirt Boss. This unit fires up within 2 pulls and is ready for work. Always ready and dependable. It does a tremendous job on cleaning off old stain and making the fence ready for new stain. I highly recommend the Dirt Boss for any residential homeowners and light commercial jobs. You will not regret this purchase in my opinion.
Date published: 2019-06-30
Date published: 2019-06-21
Rated 5 out of 5 by from Starts very easy usually on first or second pull Starts very easy, you don’t have to pull on it for hours like the other brands
Date published: 2019-06-03
Rated 5 out of 5 by from Vear easy to use This washer is very easy to use and very easy to start It starts on the first pull every time
Date published: 2019-05-29
Rated 5 out of 5 by from It’s Stihl .... so it’s awesome! I’ve had the RB400 for a year now. It’s worked flawlessly every time I’ve used it. Only issue I had is one tire was flat when I bought it. I aired it up and it was flat again next use. BUT, no biggy because I’m not rolling it miles down the street. One thing I did, and I wish Stihl did is put an hour meter on it. They aren’t that expensive and how are you supposed to know when you have hit 30 hrs to change your oil if you don’t install one? I just think that Stihl should add this. But again, I will always buy Stihl products because they ARE awesome!
Date published: 2019-05-19
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