Soap and Detergent Icon Find the best pressure washer soaps, detergents, and chemicals with our detailed reviews and buying guide

updated: October 15, 2020
Pressure Washer Soap at work.

Soaps and detergents for pressure washers are not created equal. And you can’t just use any cleaner you come across. But the combo of soap and water spray is a double whammy for grime. Just ask your dishwasher. Whereas your dishwasher has the advantage of hot water, most pressure washers don’t. They make up for that with high pressure spray. Add soap to the mix, and you can speed up cleaning tenfold.

But what’s the difference between power washer soap and detergent

Surprisingly enough, soap and detergent are not interchangeable. Real soap is derived from natural ingredients (like fats & oils) while detergents are made from synthetic substances (like carbonic compounds). Most of the “soaps” you use today are actually detergents.

When should you use pressure washer soap?

Since pressure washer soap is made of biodegradable ingredients, it will cause no harm if washed down storm drains. Some communities may have strict laws regarding that, which is why you’d want to stick with natural soaps when cleaning outdoors. Keep in mind that soaps mixed with hard water or collected rainwater may form calcium carbonate deposits that will get left behind on the surface you’re cleaning.

Man washing a driveway.
Soap cause no harm to environment.

When should you use pressure washer detergent?

If there aren’t strict laws about water runoff, and you have years of built-up grime or stuck on dirt, you’ll want to go for a detergent. Detergents are stronger than natural soaps. They’re great for getting into porous surfaces you want to pressure wash, such as wood and concrete.

Can you use dishwashing liquid instead?

Dishwashing liquid?

Avoid using dish detergents like Dawn and other household cleaning liquids because they’re not formulated to handle the high pressure spray and inner workings of a pressure washer. Those are designed specifically for removing grease and proteins left from food.

If at all possible, use only soaps and detergents designed for pressure washers and also for the type of cleaning (e.g. mildew or tree sap removal) and type of surface you need to clean (e.g. concrete or siding).


Top-Rated Power Washer Soaps & Detergents: 2020 Ratings & Reviews

1Safe outdoor stain removal
Safe, non-toxic exterior multitasker that deep cleans with peroxide

This formula from Simple Green uses the power of peroxide to remove mold, mildew, and algae stains from all your outdoor surfaces. It’s non-toxic even if ingested and won’t harm grass or landscaping plants. For use in pressure washers or by hand.

One gallon makes up to 21 gallons of cleaning solution. It’s best for environmental dirt and might not work as well with oil, road tar, and other synthetic types of grime.

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2For all house siding
Ideal for brick, wood, vinyl, aluminum and stucco house siding

Need to clean your house siding but worried about harsh cleaners? This formula from Simple Green uses the power of peroxide to remove tough stains without corroding metal and mortar or degrading plastics. As an EPA Safer Choice, it won’t harm plants, pets, or waterways.

Cleans, brightens, and rejuvenates by removing mold, mildew, tree sap, algae, and other built-up grime. One gallon makes up to 21 gallons of cleaning solution.

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3Mild multi-surface cleaner
Good multipurpose cleaner from a trusted pressure washer brand

This multi-purpose cleaner from the trusted Karcher brand is great for any outdoor surface. When used with a pressure washer, it produces a thick foam that clings to the surface to penetrate grime.

One gallon of concentrate makes up to 20 gallons of cleaning solution. It has a mild, pleasant scent, is biodegradable, and safe for your lawn and garden plants. Can be used in a bucket for hand scrubbing.

For Smaller Cleaning Jobs
  • Karcher - for Outdoor Surfaces, 1-quart
    Karcher – for Outdoor Surfaces, 1-quart
    Price: Low

    If you don’t have many surfaces to pressure wash or don’t pressure wash often, this smaller volume comes in a 1-quart size rather than a full gallon. It makes up to 5 gallons of cleaning solution. There’s a built-in measuring cup with easy-to-read gradations so you won’t waste any cleaner. Other than that, it’s the same formulation as the gallon size and is best for mild to moderate stain removal. Ideal for decks, BBQ grills, patio furniture, walkways, privacy fences, and other smaller jobs.

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4Heavy-duty exterior cleaning
Good multi-purpose detergent for a variety of exterior surfaces

This multi-purpose heavy-duty detergent from Briggs & Stratton works to remove dirt, mold, mildew, and other grime from all exterior surfaces. It’s good for patios, decks, siding, windows, etc. and is safe for lawns and garden plants.

One gallon makes up to 16 gallons of cleaning solution. Since it’s a powerful cleaner, the manufacturer recommends testing it on a small area of the surface to be cleaned before proceeding.

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5Car wash & wax combo
Biodegradable cleaner & wax combo safe for all pressure washers

This thick-foaming formula from Karcher is biodegradable and made in the USA. It includes wax for a 2-in-1 car cleaning experience. A gallon jug makes up to 20 gallons of cleaning solution. It can be used with several pressure washer attachments, including foam cannons, scrub brushes, and soap nozzles.

Unlike harsher detergents, it’s safe for your lawn and plants and can be used on decks, windows, and other exterior surfaces if needed.

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6For All Automobiles
Biodegradable, versatile cleaner that smells great and preserves wax jobs

Sun Joe Snow Foam car soap is a fast-foaming formula designed to clean gently yet effectively, leaving a gleaming surface. It’s gentle on paint, wax jobs, and metal. Yet it’s tough on dirt. Recommended for use with Sun Joe foam cannon attachment (Sun Joe SPX-FC34).

A little of this biodegradable cleaner goes a long way. Just mix 1 – 2 oz. per 5 gallons of water. Or use it undiluted if using a foam cannon.

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7For wood, brick, & vinyl
Removes stains and grime from home exteriors, walkways, and decks

Designed to be used in your pressure washer’s detergent system, this formula from Sun Joe is ideal for tough outdoor stains. Removes mildew, mold, and built-up grime from your brick, vinyl siding, concrete walkways, and wood decks.

For heavy soil, one gallon makes 5 gallons of solution. For lightly soiled surfaces, it makes 10 gallons of solution. Can be used with all pressure washers or with a mop or bristle brush application.

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8For driveways & walkways
Removes stubborn stains from driveways, walkways, patios, and masonry

Need to clean oil, grease, automotive fluids, rust, tire marks, and other tough stains from your driveway? Look no further than this biodegradable formula from Simple Green. The power of peroxide helps remove grime from hard surfaces such as concrete and brick.

One gallon makes up to 21 gallons of cleaning solution. Siphon directly from the jug or pour in the detergent reservoir of any pressure washer. For very stubborn stains, apply and scrub with a bristle brush.

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9Cleans outdoor structures
Removes tough grime from decks, fences, & other outdoor structures

This formula from Simple Green uses the power of peroxide to remove stubborn grime from all your outdoor structures. Ideal for decks, fences, pergolas, gazebos, carports, sheds, and more. The non-toxic, biodegradable formula is safe for plants and waterways.

One gallon makes up to 21 gallons of solution. Siphon directly from the jug or pour in the detergent reservoir of any pressure washer. Or apply manually with a bristle brush.

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10For cars and trucks
Non-toxic detergent for all vehicles compatible with all pressure washers

This concentrated cleaner from AR Blue Clean comes in a gallon jug and makes up to 30 gallons of cleaning solution. It’s designed specifically for cars and trucks, but also works well with RVs, boats, and other vehicles.

The non-toxic, non-corrosive formula is safe for rubber, paint, glass, plastics, and vinyl. It can be used in a foam cannon or in a traditional wash bucket. Compatible with all pressure washers.

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Why you can’t use regular soaps in pressure washers

Pressure washers are a bit finicky in that they require special soaps and detergents. Regular soaps such as laundry, dish, or household cleaners are not formulated to withstand the high pressure a power washer delivers.

Foam-damaged washer.

Think about a jacuzzi tub. If you’ve ever accidentally poured bubble bath in while the jets are on, you probably witnessed a fast-moving avalanche of suds that flowed over the sides of the tub. A similar thing can happen if you use a regular laundry detergent in a high efficiency front-loader. It’s the same concept. Specific cleaners are designed for the specific pressures and velocities of specific appliances.

So, when looking for a pressure washer soap or detergent, make sure it’s one designed specifically for pressure washers. Many of them can be used with any pressure washer, but be sure to check your pressure washer owner’s manual to see if the manufacturer recommends any specific cleaners and to see the recommended amounts.

The better you follow the recommendations, the longer your pressure washer will last.

What chemicals are used in pressure washer soaps & detergents?

There are 3 basic terms you’ll see thrown about on labels and product descriptions. Here is a very basic rundown of what they’re for.

  1. Cleaners – Dirt removal
  2. Sanitizers – Quickly (less than 30 seconds) kill up to 99.9% of bacteria
  3. Disinfectants – Kill ALL microorganisms within 10 minutes

Car Wash and Wax Soap.
Complex composition is required for best results.

This is a list of chemicals you’ll see on many pressure washer cleaners & their general intended purposes:

  • Citric acid – Removes stains from concrete and wood
  • Oxalic acid – Removes rust & other stains
  • Vinegar – Very gentle cleaning for kitchen surfaces, windows, even fresh produce. Polishes brass, neutralizes odors, safe for pretty much any surface
  • Sodium hydroxide – May be called “caustic”. Quickly dissolves fats, oils, and grease on glass, steel and other surfaces.
  • Sodium hypochlorite – Strong disinfectant & stain removal
  • Bleach – Mix of sodium hypochlorite & sodium hydroxide. Very effective sanitizer & disinfectant. Ideal for mildew and mold removal
  • Ammonia – Great for glass and stainless steel
  • Potassium hydroxide – Essential in making soft or liquid soaps

Concerned about exposing your garden plants, waterways, pets, & kids to cleaners?

EPA Safer Choice logo

Well, you’re in luck. Many pressure washer cleaners are now biodegradable and won’t hurt your lawn or landscape plants. Several are actually endorsed by the EPA as a “safer choice” so they won’t harm wildlife or waterways. Some are even orally non-toxic so they won’t hurt your child or pet if they were to ingest them.

Look at the labels. The safety status should be easily visible. If in doubt, you can always contact the manufacturer or get hold of the MSDS sheets for detailed ingredients and their risks.

What about homemade pressure washer soaps and detergents

We get it. You’re concerned about costs and green living. But…we can’t recommend making your own pressure washer soap or detergent for a few reasons. One being that there are so many great choices already on the market that are environmentally friendly.

Also, by the time you gather up separate ingredients to mix up your own cleaner, you won’t be saving much money and certainly won’t be saving time. A jug of concentrated cleaner isn’t that expensive and goes a long way. Some of them make up to 30 gallons or more of cleaning solution.

Amateur chemist.

Lastly, as we stated above, pressure washers require specific cleaners and dilutions that you may not be able to replicate at home. If any measurement is off, you risk damaging the pump and inner workings. Most likely, your warranty won’t cover any damage incurred from using an unapproved cleaner.

That’s not to say you can’t use a little homemade remedy to help the cleaning process. Think pre-cleaning. Use an undiluted white vinegar to spray on mildew and mold stains before you clean with the pressure washer. Let it soak or scrub it in, then clean with the pressure washer. You may not even need soap, and it’s totally safe for the environment.

Pre-treating with a bleach solution is also an option, though you have to be careful around plants and shouldn’t let it soak into the soil. It’s best to cover the area below with a tarp if you’ll be using bleach. But for stain and odor removal, killing mold and mildew, and disinfecting, bleach is the king.

Whatever you decide to use, don’t be afraid to try different soaps and detergents, different dilutions, and different application methods. It may take some trial and error before you find what works best for your cleaning needs.

Alex Woodward
Alex owns a home improvement and restoration company in Vancouver. He obtained his Bachelor’s degree in Construction Management from Saskatchewan Polytechnic and is a NARI Certified Remodeler. His team does a wide range of home restoration products, both interior and exterior.
image description Comments
Peter, Birmingham, AL
August 23, 2020 at 9:21 pm

What a great discussion!
We are about to purchase a low-cost pressure washer for light jobs and know NOTHING about the washers or the cleaners
Your discussion is great and seems very thorough
(I was a biology + chemistry major back around the industrial revolution and appreciated the reminder about the chemistry and physics involved in the way these solutions work and flow through these pumps. I am TOTALLY the kind of person who would be likely to say, “I’ll just try some reeeeeally dilute DAWN! What could go wrong? After all . . . I’M A DOCTOR!”)
We’re going to look into the Simple Green brand
We also are going to bookmark your name and check back with other questions 😀

Faron Tolbert
April 28, 2020 at 6:23 pm

I’m looking for a powerful pressure washer detergent for concrete and houses

Troy R Reed
April 10, 2020 at 5:40 pm

Nice article. I have studied chemical mostly truck wash, car wash, degreaser ect. If you would like to contact me, feel free to.

image descriptionAdd comment

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