A Guide to Choosing the Best Pressure Washer Soap, Chemicals & Detergents

Pressure washers make cleaning easier, but adding detergent or soap makes it even faster. True, pressurized water removes dirt, but soap gives it more energy to wash away the grime.

With most types of detergents, you don’t need to use hot water for the cleanup. Before you buy a pressure washer detergent or soap, you should spend a sufficient amount of time learning about them before you pick one for your specific purposes.

Detergent for Washing Concrete

Simple Green 18202 Concrete and Driveway Cleaner

The 18202 has been formulated specifically for driveways and other concrete surfaces. One jug is good for 11 washes, and each one has enough power to remove grime, grease and oil on these surfaces. You can also use the Simple Green to eliminate discolorations and stains.

Unlike other pressure washer detergents, the 18202 doesn’t cause corrosion so the surface doesn’t get damaged. Since the 18202 is formulated specifically for concrete, you can use it on sidewalks, driveways and walkways. In fact you can use this formula on any surface as long as it’s concrete. Designed for both pressure washers and manual use, the 18202 is safe, non-toxic and economical. You only need to use a little to get a good result.

Detergent for Fence and Wood Decks

Krud Kutter DF01 Blue Pressure Washer Concentrate

Apart from providing a 2000 square ft. coverage, the DF01 has Sporex, a special additive for removing algae, mold, moss, mildew and other stains. Once you’ve applied it, the formula dissipates the stains. The DF01 also eliminates stains caused by acid rain, tree sap, etc. The DF01 also has the advantage of being biodegradable and nontoxic.

The formula also has unique surfactants that pierce the surface without causing any damage. While it’s meant for wood decks, you can also use this to remove oxidation and chalking on various wood surfaces. The directions for using the product are clear, and you just need to leave it on for five minutes before you wash it off.

Detergent for Vehicle Cleaning

Karcher Car Wash & Wax Soap for Pressure Washers

If you’re looking for an effective and safe cleaning solution for your car, the Karcher Car Soap is worth looking into. With a gallon of this, you’ll have enough to clean your car or even a boat. Usage and mixing instructions are provided on the label, but most go with 10 cups of water per 1 cup of the Karcher.

There are a lot of pressure washer detergents for car washing, but the Karcher has the advantage of being safe to use and proven effective. The formula concentration is high, but it removes dirt without causing any discoloration. The formula also works great for on different types of car finishes, so that’s another plus.

Detergent for Multipurpose Cleaning

Simple Green 13421 Pro HD Heavy Duty Cleaner

The 1 gallon Pro HD contains a noncorrosive, nontoxic formula, and it is meant for heavy duty cleaning at home, commercial and industrial applications. Its formula is powerful enough for use in commercial baths and kitchens and it’s also suitable for ultrasonic cleaning, washing components and pressure washing.

The Pro HD also works for automotive cleaning, industrial equipment, floors and walls. The Pro HD also lives up to its name of being an all-around cleaner with its ability to remove dirt off appliances, plastics, chrome and floors. While it’s very effective when used with a pressure washer, you can apply it in different ways.

Detergent for House & Siding

Krud Kutter HS01 Green Pressure Washer Concentrate

The HS01 cleans up to 2000 square feet, more than enough for most house siding. The typical mix is 1 cup HS01 and 10 cups of water, good enough for 11 gallons. Once the mix is ready you can clean leaves, fungus, mold and other deeply embedded dirt. The HS01 also contains surfactants that remove dirt, grease and stain.

The HS01 shares many features with other Krud Kutter cleaning solutions, but it is most effective for exterior siding. Its formula is potent enough for different siding materials like aluminum, vinyl and wood. You can also use this on cedar tile, shingles, fiberglass as well as walls.

Now let’s take a look a couple of pressure washers you can use with these soaps and detergents.

Gas Pressure Washer for Detergent

Simpson Cleaning MSH3125-S

The Simpson MSH3125-S is built for home use and also for those who run a small shop. Running on a Honda GC190 engine, the MSH3125-S makes it easy to use soap or other cleaning solutions. While it doesn’t come with a tank detergent, any water jug should do fine.

The MSH3125-S is equipped with a soap nozzle and siphon hose injection system. All you have to do is insert the hose in the detergent, hook up the soap nozzle and it is set. As you spray the surface, the soap is mixed with the water.

The MSH3125-S uses a 25-foot x ¼ inch MorFlex hose for easy cleaning, and the onboard storage ensures you don’t misplace any of the components. Apart from the soap nozzle tip, there are other tips for more flexible spraying. The pressure washer itself is made from welded steel for durability.

Electric Pressure Washer for Detergent

AR Blue Clean AR390SS

The AR390SS pressure washer is equipped with downstream injection, and they have a detergent tank. There is a soapy detergent nozzle tip so everything you need to get started is included.

The unit runs on a 1.6 motor and has a 30 foot hose so you can clean those hard to reach areas. The Quick Connect nozzles are easy to put in place. Once you have the soap nozzle, you can use it to remove grime, mold and other dirt.

The washer uses an axial cam pump and Simpson’s PowerBoost tech for better cleaning power. The spray gun has a lock out feature, and with 2000 psi and 1.4 GPM, it’s got the power to clean up outdoor furniture and vehicles. But its biggest strength is making it easy to add the cleaning solution you need, speeding up your work.

What is the Difference between Soaps and Detergents?

There are many types of detergents, and soap is one of them. Made from a combination of animal and plant oils, soap is mixed with glycerin, salt and other ingredients to produce the final product. When mixed with water, soap is able to dissolve grime, dirt and stains. Other types of detergents are synthetic and use different types of chemicals.

Cleaning Efficiency: Soap vs. Other Detergents

Efficiency depends on what you’re cleaning and what type of soap or detergent you bought. Concrete and wood are more easily cleaned with detergents, and there are also cleaning solutions formulated for vehicles so it doesn’t damage the paint.

Soap is most effective for light cleaning tasks. If high pressure water isn’t enough to remove the dirt, add soap and dirt should come off. One of the benefits of using soap is its biodegradable nature, making it easy to wash off. The drawback is you can only use it with treated water, i.e. soft water.

If you combine hard water and soap on a pressure washer, it’s going to leave mineral traces on the surface you just washed. Detergents however, can be used on both. But the fact is you don’t have to pick one over the other as the two can be combined for optimum cleaning.

How Pressure Washer Injectors and Dispensers Use Soaps and Detergents

Detergents are inserted into the water flow either after (upstream) or before (downstream) the pump. If it’s downstream, the injector has to be combined with a soap nozzle tip so the solution can be moved from its container into the hose. This is only a general description, as pressure washers use different mechanisms and systems. For more information, read the manual that came with your pressure washer.

Home and Commercial Pressure Washer Cleaning Solutions

There are many types of cleaning solutions, soaps, detergents and chemicals used with power washers. However, they can be divided into two broad categories: home and commercial use.

The biggest difference between the two is commercial cleaning solutions are more powerful. Professional cleaning solutions can also be purchased wholesale and allow you to make custom preparations.

  • If you only use the pressure washer once in a while, or there’s not a lot of dirt buildup, residential cleaning solutions will do.
  • If you own a car fleet, a large building or use a pressure washer every day, a commercial or professional grade solution is the better option.

A commercial or professional cleaning detergent is not limited to those applications. If you’ve got a large property and need to do a lot of cleaning, a commercial grade cleaning solution could be worth buying.

Types of Cleaning Chemicals and Solutions

Pressure washer cleaning solutions vary in terms of strength and purpose, and manufacturers make this clear in the product label. Some detergents are solely for dirt removal, while disinfectants and sanitizers eliminate bacteria and microorganisms respectively. Depending on the strength, the detergent may take a few seconds or several minutes to work.

Among the most common ingredients you’ll find are:

  • Potassium Hydroxide: common soap ingredient.
  • Ammonia: found in stainless steel and glass cleaners.
  • Sodium Hydroxide: sodium hydroxide is often used as a steel and glass degreaser.
  • Sodium Hypochlorite: known for its disinfectant properties, it’s also effective in getting rid of stains.
  • Bleach: bleach is a powerful disinfectant and sanitizer. Be careful when using this as it can damage delicate surfaces.
  • Oxalic Acid: oxalic acid is used to get rid of rust.
  • Citric Acid: this is often used to get rid of stains, clean wood patios and decks and concrete surfaces.
  • Vinegar: some cleaning solutions use vinegar as it’s been proven effective on various surfaces.

There are other ingredients that you’ll come across, but these are the most common and have proven effective on the surfaces mentioned.

Tips and Warnings

Use detergents and / or soaps only if the surface specifically states that you can. You should also exercise caution, i.e. wear safety glasses when mixing these chemicals. Here are some other suggestions

  • Look for detergents that are eco-friendly and won’t cause damage to your garden.
  • Buy detergents with biodegradable ingredients.
  • If you’re mixing the ingredients, follow the directions clearly and don’t add more than is necessary.
  • If you’re not sure what cleaning solution to use, start with water only. Increase the pressure to the highest level. Combine the water with soap if water alone doesn’t do the work. Only then should you use detergents.
  • Inspect your pressure washer before using it. If there is a defect with the spray gun, hose or other components, the solution might spill and cause damage on other surfaces.

Before you use the pressure washer, remove as much of the debris on your siding as possible. By doing this, you’ll help the pressure washer and the detergent remove the underlying stains.

This might sound obvious, but make sure the detergent or soap is compatible with the pressure washer. Also check if the detergent works at a specific pressure level. Some of these detergents work better at high pressure but others don’t. It’s also a good idea to spray over a small section to ensure it’s good for the siding.

You can make things easier for yourself by getting a pressure washer with a detergent tank. With a tank built in, you’ll have an easier time mixing and matching the soap and detergents to meet your needs. Depending on the surface you’re cleaning, you may need different types of detergents, so a tank that automates the preparation and spraying will help.


If you look at pressure washers online, you’ll notice that majority have nozzle tips for soaps, underscoring its efficiency. Even if you have a powerful pressure washer, you’ll still find detergents more useful with a cleaning solution.

If you have never used a cleaning solution with your pressure washer, it might prove difficult to figure out which solution to use. With this guide you’ll now know where to start, what to buy and where to use them.

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