Applying Detergent With Pressure Washer Systems

The Best Way To Apply Detergent With a Pressure Washer

Using a pressure washer to apply detergent is a common and effective way to clean various surfaces. Here’s a general guide on the best way to apply detergent with a pressure washer.

Choose the Right Detergent

  • Use a detergent specifically designed for pressure washers.
  • Avoid using bleach or other harsh chemicals that may damage the pressure washer or the surfaces you are cleaning.
  • Different surfaces may require different types of detergents.
  • For example, there are specific cleaners for siding, concrete, vehicles, etc.
  • Our complete line of detergents here: Chemicals

Read the Manual

  • Always read and follow the manufacturer’s instructions for your pressure washer and the detergent you’re using.
  • Ensure you have the chemical SDS and are aware of all safety precautions.


  • Most pressure washer detergents need to be diluted with water.
  • Follow the instructions on the detergent container for the correct dilution ratio.
  • Use a clean bucket or container to mix the detergent and water thoroughly.

Attach Detergent Injection System or Soap Nozzle

  • Many pressure washers come with a upstream detergent injection system or a soap nozzle.
  • Downstream injection is better for hot water machines because detergent does not run through the pump or coil, potentially causing harm to seals/pumps and cause scale build up in the coils.
  • Also, the use of foamers can be a great accessory in the cleaning process.
  • Attach the appropriate accessory according to your pressure washer’s design.
  • Our foamer selection: Foam Kits
  • Our downstream injection systems: Chemical Injectors

Apply Detergent

  • Start from the bottom and work your way up to prevent streaking.
  • Apply the detergent evenly across the surface, ensuring good coverage.
  • Allow the detergent to dwell on the surface for a few minutes to break down dirt and grime.
  • Do not let the detergent dry on the surface; if needed, mist it with water to keep it wet.

Scrubbing (if necessary)

  • For stubborn stains, you may need to scrub the surface with a soft brush or sponge after applying the detergent.
  • Our complete line of brushes: Brushes and More


  • Switch to a high-pressure nozzle or remove the detergent injection system to rinse away the detergent thoroughly.
  • Again, start from the top and work your way down.

Adjust Pressure

  • When rinsing, adjust the pressure to the appropriate level for the surface you’re cleaning to avoid damage.
  • Our variable pressure wands: Variable Wands

Final Rinse

  • After using detergent, perform a final rinse with clean water to ensure all detergent residue is removed.


Remember that not all pressure washers have a detergent injection system, and in such cases, you might need to apply detergent manually and then use the pressure washer for rinsing. Always follow safety precautions, wear appropriate protective gear, and test a small inconspicuous area first to ensure compatibility with the surface you’re cleaning.