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How to Add Soap to Pressure Washer

Just look at the state of your driveway ― all those dirt streaks, tire tread marks and guano drops destroying your curb appeal… did we hit the nail right on the head? You, my friend, need to clean this mess ASAP before the neighbors start looking at you funny because it will happen.


Karen is just around the corner and she just might call you out for destroying the neighborhood, not that the state of your house is any of her business. Nevertheless, we are here to save the day with pressure washing.


So, breakout the machine and get it ready to give your house a shiny new look. But wait… there’s been a change in plans. Come to think of it, a simple pressure wash might not get the job done. Those dirt marks might get washed away but chances are that the tire tread marks will prove to be a little stubborn. This is why we suggest using soap in your pressure washer. Great idea, right!


Now, the question is ― how to add soap to pressure washer?


There are two ways to do this: install a chemical injection kit or go old school by using a bucket and siphon tube. The former is quite complicated, whereas the latter is easy peasy lemon squeezy.


But first, let’s talk about what type of soap you can use:

Chemical Guys CWS_402_64 Mr. Pink Super Suds Shampoo & Superior Surface Cleanser, 64 oz, 64 fl. oz, 1 Pack

Detergent vs. Soap – Which Is Best for Your Pressure Washer

As mentioned above, sometimes water is not enough to clean away dirt. Enter soap… or detergent. So, what to choose?


Although you can make DIY soaps for your pressure washer, we wouldn’t recommend it. They might not be friendly to your pressure washer clog, the nozzles or filter.


There are specific liquid soaps and detergents made for pressure washers. Not only are their chemical composition easy on the machine’s parts but they also do a better job at wiping dirt. Depending on the type of surface you are planning to clean, you can switch between soap and detergent.


Since soap is a product of natural ingredients, it isn’t that harmful to the environment. Soap is best for washing your house’s siding, swimming pool tiles and other delicate surfaces. On the other hand, detergent contains artificial materials and is less biodegradable, which makes it perfect for harsh surfaces such as your pavement and driveway. Keep in mind that every soap and detergent has a different chemical makeup based on the surface you want to clean.


Always read the ingredients before buying any cleaning solution. If the list says “bleach” then avoid this cleaner as it can damage your pressure washer from the inside.


With that said, following are steps on how to add soap to pressure washer:


*If your pressure washer already has a tank then all you need to do is add the appropriate amount of liquid soap into it. If you are planning to install an injection tank then you have two options: an upstream kit and the downstream kit. After connecting the siphon tube to the chemical injector, you can follow the steps outlined below. Since the kit makes the connection process time consuming, we don’t recommend choosing this option.


With that said, let’s move on to the steps:

Chemical Guys CWS_402_64 Mr. Pink Super Suds Shampoo & Superior Surface Cleanser, 64 oz, 64 fl. oz, 1 Pack

Equipment Needed

  • Pressure Washer
  • Bucket
  • Liquid Soap
  • Hose
  • Weighted Strainer
Chemical Guys CWS_402_64 Mr. Pink Super Suds Shampoo & Superior Surface Cleanser, 64 oz, 64 fl. oz, 1 Pack

Adding Soap to Your Pressure Washer

Step #1

Cover the Plants or Any Other Nearby Items

Place a tarp over your potted plants to prevent the soapy water form hitting your precious roses. For better cleaning results, we suggest that you use hot water. The high temperature will loosen up the dirt quickly and you will be able to cover a bigger surface faster.


Step #2

Create Your Soap Bucket

Now, let’s MacGyver our way to creating a soap tank! Attach the hose to the weighted strainer and place it into the bucket. Make sure that the strainer is touching the bottom of the bucket. Attach the hose’s other end to the inlet valve. Fill the bucket with soap. If you have bought a concentrated bottle of soap then check the instructions on the back to see how many parts water and soap should be mixed.


Make sure that solution is liquid enough to be easily siphoned into the pressure washer. If the solution is thick, the nozzle will get clogged.


Step #3

Change Nozzles

Soap works best with a low pressure nozzle. Generally, the green nozzle is used for cleaning most surfaces. When using soap or detergent, the black nozzle does a better job. It has a large orifice and decreased water velocity. This increases the pressure and pulls the soap faster up the house. As a result, you are able to apply soap easily and quickly on every surface.


Step #4

Wash in an Upward Direction

To avoid leaving streak marks on the surface, start washing from the bottom and overlap as you move upwards.


Step #5

Let the Soap Sit for a While

Once the entire surface is covered with soap, let it sit on the surface for a while to weaken the stains. If it’s sunny outside, wash the surface faster.


Step # 6

Pressure Wash With Clean Water

Remove the hose from the bucket filled with soap water, press the trigger for a couple of minutes to flush out any leftover soapy water, switch to a high-pressure nozzle and pressure wash the surface again.

Karcher Multi-Purpose Cleaning Pressure Power Washer Detergent Soap, 1 Gallon

Final Thoughts

As you read, adding soap to your pressure washer is not that hard. You don’t need any heavy tools or extra equipment. In case you are planning to buy a new pressure washer, we suggest that you get one that comes with a tank. This will remove all the hassle of connecting the hose to the pressure washer. As for the cleaner, don’t forget to check the ingredients list. To make sure that the soapy water hits the appropriate places, use a bigger nozzle with low pressure.


And that’s how you can add soap to pressure washer and clean any surface you want.


About Chris

When Chris first bought a house, he quickly realized that he was now going to need to be a weekend handyman. Every project that he worked on, he kept realizing that he needed more and more DIY tools. Chris is also someone who likes to do a lot of research before making large purchases. Since he had already done most of the research, Chris decided to put the info that he accumulated about his favorite daily tools onto