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Welcome to the World of Pressure Washers

There is a lot to know about pressure washers in order to get the job done correctly, quickly, without damage and on a budget. You want to know what you need, what are the smart options, how to get your money's worth, and what will help you finish up quickly and move on.

Let's walk through everything you need to know to be a pressure washing pro!


What is the difference between Power Wash and Pressure Wash?

Most people use the phrases "pressure washers" and "power washers" interchangeably. Pros know that a power washer has a heating element designed to do a much faster, cleaner job, especially for removing oil and grease. Power washers, also known as hot or hot water pressure washers, are also a great idea if working in a cold climate where the hoses may actually freeze up.

Otherwise, pressure washers and hot water or power washers are pretty much the same. They both come in wide ranges of PSI/GPM ratings, and with various accessories.

Power washers are relatively more expensive and require more maintenance, with the heating element to consider. Some pros prefer to use a regular pressure washer running chemical detergents. Others find that if usually cleaning greasy messes, the power washer pays for itself in not spending so much money on detergents. There are component heaters designed to be put inline with pressure washers, but they may not work together all that well.


What Is PSI in a pressure washer?

The average home power washer consumer focuses on one number, the PSI. PSI means pounds per square inch and leads off on the signs in hardware stores.

PSI means the absolute maximum force that is coming out of your pressure washer. A stronger PSI means more cleaning power - and more risk of damage if on a delicate surface. The highest PSI always comes from a very narrow tip at close range, with lower PSI coming from wide angle tips.

What does GPM Mean on a pressure washer?

The other number that is always listed is the GPM rating, or Gallons Per Minute. In the same way that electricity is measured, both the pressure and the flow are very important.

GPM measures the total amount of water that can flow. Clearly a wide angle tip pushing a lot of water can remove dirt much faster than a low GPM flow.

Total Cleaning Power Calculation

Most people care about the overall cleaning power of. a pressure washer. Some specific power washer users may care more about the PSI or the GPM depending on the application, but who knows exactly what the future holds? As a rule of thumb, pros multiply the PSI by the GPM to get an overall cleaning power rating for the general use of a power washer. It's easy to understand. When looking over power washer models, one may have a very high PSI but a very low GPM, and another could have a very low PSI but a very high GPM. A third model that has a pretty high PSI and a pretty high GPM will have way more general cleaning power than either of the first two.

Watch out for MAX PSI versus "working" PSI

There is some hanky panky going on with some ratings on some models of pressure washers. Do not be fooled by a rating that includes a Max PSI rating AND a "working" PSI rating, sometimes known as "rated" pressure. The working PSI is all you care about. Inflated claims for max PSI can be off by as much as 30%. These manufacturers claim the max number is the amount the power washer can push out of the wand briefly, or perhaps without a tip on it at all, being used for, say, rinsing. The Better Business Bureau and others have looked into this, but they are letting it slide, since perhaps the max rating should be known as the power washer might hit that rating for a short time but long enough to damage a delicate surface.

Pressure Washer Classes - Use Enough Power for the Job

Pros know that using a too small tool will take seemingly forever to do a big job, if it is possible at all to finish, On the other hand, using a shotgun as a flyswatter is a very bad idea. Of course, you can always use a different, wider nozzle to step down from a higher PSI, and some pressure washer models can lower flow on demand. But an underpowered washer cannot be stepped up. Focusing only on the PSI, most people agree that there are general classes of appropriate pressure washers for specific tasks. Choose a power washer based on what it will be used for.

What PSI is needed for your specific task?

500 PSI or less: For delicate jobs. Should not hurt paint on cars, ok for light furniture like wicker, good to not destroy lightweight screens.

2000 PSI or less: better for grills, heavy duty outdoor furniture, tougher screens, light mildew, cleaning concrete that is not that dirty.

2000 to 3000 PSI: Good for regular concrete, heavier stains, decks, fences, siding, mold and mildew. Can power small surface cleaning attachments.

3000 to 4000 PSI: Can power larger surface cleaner attachments, and therefore clean pavement, asphalt, and heavier stains, mold, and prep for paint.

4000 PSI and over: this will drive very large cleaner attachments, tackling big jobs. Paint stripping and even graffiti removal is possible at this level.

What Power Source do you Want / Need?

In the bad old days, the only power washers available were large, gasoline powered, noisy, and you could cut off your foot with the pressure or crush one moving the washer around. Technology is marching on, and there is now a wide range of choices on how your power washer should be powered: Gas, electric, or now even battery powered are options.

Electric pressure washers have become very popular. They can be very small and lightweight, and require no maintenance, though on the flip side usually replacing them is the only way to fix them. There is a real limit to how strong they can be, maxing out around 2500 PSI, though this is going up. Electric washers are usually quiet and don't spew exhaust fumes. Mixing electricity and water is kind of scary, but most modern models come with circuit breakers built in, or they should be used on a GFCI socket.

Battery powered pressure washers are now entering the market. These can be very convenient for marine use, where you can have NO cords OR hoses if you can use lake water while cleaning boats or small docks. These washers run on power packs like modern electric drills but are not yet that strong or long lasting.

Traditionally, gasoline pressure washers are much louder, heavier, require gas, oil and maintenance, and need ventilation. But the tech here keeps getting better and better as well, Some engines like the Honda are quiet and very powerful. Gasoline is still the choice for heavy duty applications. And improving small gas engines are slowly edging into the space of electric power washers.

Commercial Pressure washers versus "Residential"

Pretty much all the electric power washers available are residential, despite how they may label themselves. If you are a professional power washer working on a daily basis on big jobs, you need the heavy duty PSI and GPM that is only provided by a gas engine.

Even good, high powered gas engine setups are not enough for pro use. The real difference between having a home power washer and a commercial power washer is in the reliability of the equipment.

The Engine: Reliability by Design

Commercial grade pressure washers use engines that can take daily abuse with graceful failure. For example, a commercial presser washer might use a Honda GX engine, where a home pressure washer might have a Honda GC series. They are both Honda's, which is usually nice, but differences between the two give insight into the general case, even though tech keeps evolving and these models may change.

A commercial engine tends to have around a three year warranty, versus around three months for residential. A commercial engine like the GX has an automatic shut off when a low oil condition is detected, missing on the GC. The GX has a fuel shutoff valve not found on the GC. The fuel shutoff valve doesn't sound like a big deal, but combined with a non-integrated on/off switch on the GX, fuel can be run off after use if the washer will be stored for a while. This prevents the carburetor from gumming up, plus closing the fuel shutoff valve keeps the gas from mixing with the oil if there are any bumps during transport in the back of a truck. Commercial grade means a cast iron bore versus an aluminum bore, and a commercial engine is usually mostly metal versus mostly plastic parts in a residential model. Commercial grade engines tend to have other nice features, like a way to run safety lights directly off the engine. Just like cars, an engine with electronic fuel injection may cost more, but will give easier starts and improved fuel economy.

Pump design for Commercial Pressure Washers

The other key component of power washers is the pump. Many power washing brands seem to not want to give details of the pump design,, but all pressure washers use reciprocating plungers or pistons. Commercial grade washers should have a triplex pump running on a camshaft driving plungers, and should last for thousands of hours with no issues. Smaller washers can have pistons driven by axial or wobble design using less efficient springs. Really hardcore power washer experts may prefer certain pump brands, which may or may not be the same as the manufacturer. AAA is a well known pump manufacturer that provides triplex pumps to many other brands.

General Considerations:

A loud pressure washer might be a problem for some, but no issue for others. The size and weight of a pressure washer could be important, or not so much for a bigger team with a bigger truck and big jobs. For a larger pressure washer, many pros like the "pull behind" style, mounted on wheels with a handle, often with a small "bull bumper" bar on the front for protection. Many like the full professional look and protection of the "roll cage" design, where the entire unit is protected by being wrapped by steel tubes. If you or your team is prone to dropping lumber on your power washer, or rolling it when unloading/loading, the roll cage is a great option.

Accessories - Actual Necessities, Plus More

The action of the pressure washer is delivered through a hose and the "wand" that holds the nozzles, or connects to cleaning attachments .


Low budget pressure washers may come without a sufficient variety of nozzles, which must then be purchased separately. A good set will include 0, 15, 25, and 40 degree spray nozzles, usually color coded and marked, plus a soap nozzle. Sometimes a twist adjustable nozzle is provided, which can be fine for home use. All of these components should attach and come out easily, using standard pneumatic style quick connectors, usually 1/4 inch. When replacing or adding nozzles, make sure they match in the connection size, AND are rated to handle the PSI of your washer.


The hose that is supplied with a residential model has been matched with that washer, and will usually last the life of the pressure washer. If a replacement hose is needed for a larger pressure washer, be sure that the new hose has a sufficient PSI rating to handle the load. Be careful not to "upgrade" to a larger diameter hose, as this may reduce your pressure. This can also be an issue if adding a hose that is a lot longer than the original hose.

Wands / Lances / Guns

Wands can be also known as "lances" or "guns" depending on the handle style. Simple plastic wands for small home electric power washers rarely have any troubles. Commercial washer wands are usually made of metal, yet they need to be light enough to comfortably use. This means they are easy to bend, crimp, pinch, or even break in heavy duty use, or being stepped on or run over. Some lances are telescopic, which can be a great feature, but are actually quite delicate when fully extended. Even when taking care not to lay the wand flat on the ground or lean it against a wall where it is in danger, commercial wands will need to be replaced eventually. Make sure the PSI & GPM ratings and connections match up. If replacing a wand on a gun, make sure the threads match. Usually the threads are M22 but do a quick google to check.

Surface Cleaning Attachments

The most popular and useful accessory for a power washer is a surface cleaner. These come in all shapes and sizes, but the general idea is that instead of using a spray nozzle to clean a deck/driveway etc, the power washer attaches to a round disc that converts the spray into a rotary surface cleaner. The professional ones usually have caster wheels and a long handle that makes the setup look something like a lawnmower. The speed and excellence of cleaning floors etc. this way is really striking, and will pay for itself in time savings quickly. Even the rotary surface cleaners that just hook on the wand can make a huge difference. Of course, make sure ratings and connections match up when purchasing.

Foam Cannons

Washing a car is an ideal time for a foam cannon, which is a cool name as well. Foam cannons are attachments to a pressure washing gun that look like a professional spray paint setup. They may be called foam nozzles, or foam jets. They have a screw on bottle reservoir for holding detergent, and a sawed off looking short wide wand sticking out. They take the water from your pressure washer and mix it with air and soap to spray foam over whatever you are washing. Most come with different nozzles or other way to adjust the spray, and may have larger or smaller bottles. Most pros think you need a pressure washer of at least around 1,000 PSI and a GPM of 2 or better to have a good foam cannon experience. On the other hand, some report leakage from the foam cannons as time goes by in high pressure use. Make sure the foam cannon matches up to be hooked up to your pressure washer, and can handle your PSI and GPM ratings. Some foam cannons are rated up to 5,000 PSI and 10.5 GPM, others are really designed to just be used with a regular water hose, not even a pressure washer.

Soaps, Detergents, and Cleaner Additives:

Most larger power washers come with a way to inject cleaning solutions into the wand after the pump. These liquids come in many varieties, formulated for specific uses. Proper use of solutions will greatly speed cleaning. There are solutions for cleaning vinyl siding that include peroxides to brighten the vinyl without destroying it. There are grease cutters, formulas for concrete cleaning and paint / graffiti removal, etc. No matter how tempting, experts agree not to use bleach. In the bad old days, bleach would destroy the pressure washer's seals. It still will shorten the life of accessories and possibly cause safety issues.

Brushes, Gutter Cleaners, and More

People love their pressure washers, and suppliers love those people! Various companies make different types of brushes to attach to a wand for use in cleaning cars, siding, etc. There are attachments designed to curve up and around to help clean gutters. There are drain unblockers, which look like bullets to work down and clean out drains. There are power brooms, which have three or four nozzles mounted on wheels to sweep away debris like leaves. There are add on pressure gauges, and little gatling guns for rapidly switching nozzles without losing them. Aftermarket pressure washer hoses can come on reels mounted on wheels. There will be still more options by the time you read this, but in all cases make sure the accessory matches up with your rig for ease of attachment and safety, being rated for the correct PSI and GPM.

That's about it! Congratulations, you are now more of an expert on power /pressure washers than most people will ever be! Enjoy the Zen of a positive power washing experience.

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