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​How to use a pressure washer: A guide for beginners

Pressure washing is a great way to clean and restore all kinds of surfaces around the exterior of your home. Here's what you need to know to get started.

Steve Conaway Labs Manager / Senior Technical Project Manager
I am the Labs Manager for CNET's Home Division based in Louisville, KY. My interest in technology began in the early '90s, and soon after I began my double major in computer science and computer engineering. I've worked in many areas, including computer hardware, software, technology, networking, graphic design, instruction, construction, music and even ballroom dancing! 65% Ron Swanson, 25% Ben Wyatt, 10% Andy Dwyer.
Expertise I've been an outdoor enthusiast my entire life. I also renovate, flip and build houses in my 'spare' time. Paired with our test lab facilities, I write about lots of outdoor related things - portable power stations, tools, etc.
Steve Conaway
8 min read
Steve Conaway/CNET

A pressure washer can help you quickly clean large areas of all kinds of hard outdoor surfaces. You can use a pressure washer to spray off a wooden deck, siding, a car or a concrete surface such as a patio, walkway or driveway. They're great for when the old "brush and soapy water" routine would take forever. Pressure washing is also useful because it can get rid of some of those hard-to-deal-with soils like grease, tar, gum, wax or even rust. 

Read more: How to hand-wash clothes without a washer

In this guide I'm going to tell you about the basics of buying a pressure washer, what kinds of jobs a pressure washer is good for and how to apply a pressure washer to various surfaces. I'll wrap up by talking you through a few examples of a pressure washer in action. 

When do I need a pressure washer?

A pressure washer is useful for cleaning any exterior surface that has caked-on dirt, grease, plant residue or other material across a large surface area. 

To prevent injury, avoid pressure-washing anything living, whether it's people, animals or plants. If you're pressure-washing near plant beds, use garbage bags or other plastic coverings to keep the spray from damaging your plants.

Since pressure washers are mainly used for larger or dirtier jobs, it also doesn't make a ton of sense to use them on very small areas, unless it's a stain that you just can't get rid of. If it takes longer to pull the machine out and set it up than the amount of time you'll be using it, consider cleaning by hand.

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Pressure washers come in two varieties: gas and electric. The price can range from about $100 for a low-end consumer-grade model up to thousands for larger commercial units. 

The specs associated with pressure washers are pounds per square inch and gallons per minute. Psi tells you the force of the spray. GPM tells you the volume of water passing through the spray wand. 

If you want to save time and backache cleaning off your sidewalk, deck or patio, or maybe you're looking for an easier way to wash the car, look for a pressure washer with specs under 2,000 psi and 2 GPM. You should be able to find one at your local home store for between $100 and $300.

For more cleaning power -- maybe you have some tough stains on your driveway or your deck, or you want to clean the exterior of your house -- look for a pressure washer in the range of 2,000 to 3,200 psi and 2 to 3.2 GPM. These medium-duty machines, like the Brute 2800 Max PSI pictured here, are typically gas-powered, and they usually cost between $200 to $600. Most homeowners won't need a pressure washer with higher specs.

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It's important to remember that pressure washers are not toys. You will definitely want to wear protective gear and avoid spraying other living things, such as pets, plants or pesky neighbors. For comparison, a standard garden hose probably has a psi of about 60, fire hoses start around 100 psi, and a medium-duty pressure washer can have a maximum pressure of 2,800 psi. Make sure to put on eye protection when you use a pressure washer. Ear protection isn't a bad idea either for any loud, gas-powered model.

How does a pressure washer work?

The trick to getting such high psi from a normal garden hose connected to your pressure washer is the pump. Each pressure washer, electric or gas, has a pump that pressurizes the water before sending it to the spray wand.

How do you hook up a pressure washer?

The pressure washer itself has one connection for a standard garden hose to bring water to the pump and another connection that connects the pump to a high-pressure hose that has the spray wand on the end of it. Most units have some type of siphon hose for detergents, and any electric pressure washer will have a power cord.

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The spray wand of your washer should come with different interchangeable tips that allow you to customize angle of spray for each job. Changing the angle of the spray also changes how hard the water will hit the surface. The sharper the angle, the less direct pressure on whatever surface you intend to spray. 

A spray of 0 degrees concentrates the water into one small powerful stream. As you increase the angle, the spray spreads out across a wider area, which decreases the power of the spray at any one point. The greater the angle of the spray tip, the lighter the touch on the surface you want to clean. 

There is no exact guide for which tip is most appropriate for which job. The combination of spray angle and the psi rating of your washer will determine the end result. If you're not sure about the hardiness of the surface you want to spray, start with the sharpest angle tip and work your way up. 

Universal color coding should also help you decide which tip to use. Usually the tips map to the following order, from most dispersed spray angle to the most direct: black (65 degrees), white (40 degrees), green (25 degrees), yellow (15 degrees), red (0 degrees). Still, it's a good idea to check your manual to determine the best tip for the job for your specific pressure washer.

How long can you run a pressure washer?

Assuming you have correctly set up your pressure washer, there should be no real limit to the amount of time you can run an electric model. If your unit is gas-powered, the tank capacity will be the limiting factor for run time.

What's the difference between a pressure washer and a power washer?

 A pressure washer uses water at ground temperature. A power washer uses a heating element to heat the water before spraying it out. Because of the heat, power washers are more suited to removing stains containing living bacteria, like mold. Most residential washers are pressure washers and not power washers.

Can you damage concrete with a pressure washer?

Absolutely. The main contributor to unwanted surface damage with pressure washers is using the incorrect tip. If you're unsure, or if you're using a new pressure washer or washing a new surface for the first time, it's always best to start with a wide spray tip and switch to a tip with a more direct angle as needed. The white 40-degree tip is a good place to start.

You can use almost any type of liquid soap or detergent with a pressure washer, although there are pressure washer-specific detergents for jobs of all types. Your pressure washer will have a siphon hose or basin of some type, which you fill with the desired soap. Make sure any detergent cutoff valves are on, and then you can run the pressure washer as you normally would.

For a gas pressure washer, add fuel stabilizer following the instructions in your manual. Also follow the manual for instructions on how to clear any detergent. Finally, run a pressure washer pump saver through your washer by connecting it to the hose inlet. The engine doesn't need to run during this step, nor do the spray wand or high-pressure hose need to be connected. Once you see the white foam coming from the high-pressure hose connection, you're done.

For an electric pressure washer, you can omit the fuel stabilizer step.

The pressure washer in action

Anytime you start a new cleaning job, test with the spray wand tip between 2 to 3 feet from the surface you intend to clean. Give a quick test spray, to an out-of-sight area if possible, to confirm that you won't damage the surface. Even then you probably don't want to get much closer than a foot. Getting the spray tip, especially a high-pressure tip, too close to a surface can even damage metal.

To give you a sense of how to match the tip to the surface, I cleaned a few things around my own home here in Indiana with my Brute 2800 washer.

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I started with some lower-pressure jobs using the white tip. You can see in the before and after photos here that I cleaned my aluminum fence. It took mere seconds to clean any one area of the fence. 

I stepped up to the medium-pressure green tip for the underside of the mower. A couple of years' worth of caked-on lawn residue needs more power. After 2 minutes here, it looks pretty good!

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Also with the green tip, I took on the rarely used side deck of my house. The 25-degree tip is a medium-pressure tip that's good for removing surface-level stains like you see here. I plan to refinish this deck next year, but for now it needs a good cleaning. 

One thing that makes washing the deck different from some of the other jobs is that I am actually going to use a detergent to help break up the set-in stains. My Brute pressure washer, like most models, has a siphoning tube specifically for detergents. For this job where I want to clean off plant matter residue that has penetrated the wood grain, I used a product called Apache Deck & Siding Cleaner, which is for cleaning decks, fences, porches, patio furniture and wood siding. 

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Just drop the tube into the detergent bottle (this particular product has to be diluted first) and use the low-pressure detergent application tip. Once you've made a pass with the detergent, you'll need to run the siphon tube for a couple of minutes with plain water to clean the tube out before moving on. 

Cleaning the front side of this deck took less than 15 minutes. Because this deck is overdue for maintenance, you can see the washer removed paint in some areas. You wouldn't normally expect this to happen with a well-maintained wooden surface that has been painted or stained.

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For a higher-pressure job, I have some grimy concrete on the outside of my garage. There are probably various oils mixed in as well, so in this case I used a degreaser to loosen it up first to help speed up the process. As with the detergent, I simply ran the siphon tube into my diluted degreaser solution. I'm using Apache Multi-Task Cleaner, which is specifically for use on dirt, grime, oil and grease, oxidation and heavy stains. 

 After making a pass with the degreaser, I used the yellow 15-degree spray tip, which is most appropriate for this job because of its high-pressure output. If you end up with leftover stains after the yellow tip, you could always switch to the even higher-pressure, 0-degree red tip for any trouble spots, but the yellow tip was sufficient here. 

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Cleaning the concrete took about 15 minutes for this 10-foot square area. You can see in the photos how all of the dark oily discoloration is gone, and the overall color of the concrete is lighter. 

I also had the chance to experiment a bit with the different tips. I recently unearthed an assortment of smaller landscape rocks that had been buried on my property for years. I chose three at random and laid them out. In the photos, you can see what happened when I made one pass with the green 25-degree tip and the rocks all got a bit cleaner and brighter. Then I made a pass with the yellow 15-degree tip, and the results are noticeably cleaner. 

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After a final pass with the red 0-degree tip the rocks all look super clean! Notice though, while it's difficult to make out, you can also see in the close-up how the red tip carved a trench right through the one paver style block! If that doesn't convince you to wear closed-toe shoes when you're pressure washing, I don't know what will.


Beware the 0-degree red tip.

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And there you have it. I breathed some new life into things around the house without too much trouble. Pressure washing can be a great home maintenance tool. Get the right machine and be safe!

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