What Kind of Soap to use in a Pressure Washer

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If it’s your first time to use a pressure washer, you’re in for a treat. This simple, yet incredibly effective tool, is made to save you hours of cleaning time. You can say goodbye to expensive professional cleaning services. And it works for both outdoor and indoor cleaning. 

You do want to make sure that you’re using this tool the right way. One of the first questions people ask when using this tool is ‘What kind of soap to use in a pressure washer?’ Getting this right is an important part of the results you will get from your pressure washer.

What Kind of Soap to Use in a Pressure Washer

The type of soap you should be using in your pressure washer will depend entirely on the surface you are cleaning. There is not one type of soap that works with every kind of surface.

Pressure washer

For example, you should not use any powder based soap with your pressure washer if you’re planning to clean your car. Undissolved powder residue can scratch and ruin your car’s paint job.

This is why it’s important to first consider what surface you will be cleaning. Then you can choose the soap to use with your pressure washer.

What Soap Works Best on Different Surface Types

Different types of soaps work best on different types of surfaces. Dish soap will work best when cleaning your dishes, but will be absolutely useless when it comes to cleaning floors. This is a guide on what type of soap works best on different surface types. 

  • Concrete and wood surfaces

For concrete and wood surface cleaning, it is better to use detergents. They are strong enough to break through difficult stains and dirt on these rough, hard surfaces.

  • Cars, vehicles, and boats

To keep your vehicle’s paint job protected, it’s always better to use soap that was created specifically for cleaning cars or boat surfaces. Car washing soap is made to clean your car effectively, while still preserving its painted surface.

  • Wooden surfaces

You should choose to use soap that was made to be strong enough to remove common wood stains and dirt. But not too strong that it ruins the finish of your wood surface. For a wooden surface, it is best to use soap that’s specifically made for cleaning wood. 

  • Mold and mildew

The most effective way to remove mold and mildew is by buying specific soap solutions that are made for this job.

If you want to keep it simple, a mix of 1/3rd vinegar and 2/3rds water will be strong enough to remove mold and mildew. This will even keep this from growing for a long period of time. 

Pressure Washer Soap Considerations 

There are also other types of soap other than your standard store bought detergents. These are inexpensive and can be used with your pressure washer.

A scoop of laundry detergent

D.I.Y. Pressure Washer Soap

D.I.Y. pressure washer soap can be effective in cleaning through dirt and stains on all types of surfaces. To make your own pressure washer soap at home, you can mix your laundry soap with a household cleaner.

The risk of making this on your own is that you will not have full control of how powerful this solution will turn out to be. Make sure you don’t use this on fragile and easy to stain surfaces. 

The advantage of your making your own homemade dishwasher is that it’ll be cost efficient if you plan to clean large surface areas. 

Organic Vs Non-Organic Soap

It’s fair to ask if there’s a big difference between using organic and non-organic soap.

The biggest difference between the two is that the organic soap will not be of harm when washed down the drain and eventually, into the environment. It does not pose any threat to your surrounding plants and landscape either.

Organic soap is the safest choice if you want to be environmentally conscious. It is also best if you don’t want to damage any areas near the surface that you’ll work on.

On the other hand, you need to be careful with non-organic soap as it may include ingredients that are extremely harmful to the environment (and your lawn/garden). 

According to Natural Living Family, you should avoid soaps that have Sodium Lauryl Sulfate & Sodium Laureth Sulfate/ Sodium Lauryl Ether Sulfate (SLS/ SLES), Formaldehyde, Chlorine Bleach, Phosphate and Ammonium Sulfate.

These ingredients are harmful to our environment and should not be used with your pressure washer. If you use them, it should be properly cleaned up and disposed of. 

Dishwasher Soap

A common question, as most households have dishwasher soap readily available in their home, is whether or not this can be used with your pressure washer.

Bottles of liquid detergent

The answer is, yes. You can use dishwasher soap. But you need to consider what surface you’re trying to clean.

Dishwasher soap will remove light dirt and maybe even some stains. It’s not as strong as detergent and will not work as well on wood and concrete surfaces.

What Soap You Shouldn’t Use With Your Pressure Washer

It is best to avoid using solutions with a high concentration of bleach. Bleach is extremely powerful. So much so that it can actually damage the inside of your machine. It can potentially break it. 

Try your best to steer clear from using strong bleach products with your pressure washer. As you will be using a lot of water, this will require a lot of bleach. It is damaging to both your pressure washer and your environment.

Bleach can be used in small amounts. But this should not be used with large scale cleaning tasks such as the use of a pressure washer. 


You don’t have to worry too much about what soap you use in your pressure washer. The important factor to consider is what surfaces or what type of cleaning do you intend to do. 

Just for an added tip, you can always test how a drop of soap will react to the surface you’re going to work on. See if it leaves any unintended stains, or if it works well enough. By doing so, you can eliminate possible mistakes before it’s too late. 

An expert at home repair, remodel, and DIY projects for nearly 40 years. His first experience came in completely restoring an antique home. Completely redone from the inside out, and restored to its original form, the home is a featured design by renowned Southern California Architect Cliff May, considered to be the father of the California Ranch Home. Now Dennis spends his time on fine woodworking projects and tool comparisons.