Bleach to Water Ratio for Pressure Washing: Best Mix Ratio

Bleach To Water Ratio For Pressure Washing

Pressure washing is an effective way to clean the exterior surfaces of your home. Using a pressurized stream of water allows you to blast away dirt, mold, mildew and other grime. Adding bleach to your pressure washer’s tank is a common technique to boost cleaning power. However, it’s important to use the right bleach to water ratio. Too much bleach can damage surfaces, while too little won’t get the job done. In this guide, we’ll walk through the basics of mixing an optimal bleach solution for pressure washing.

How Does Adding Bleach Help With Pressure Washing?

Bleach contains sodium hypochlorite, a chemical compound that acts as a powerful disinfectant and stain remover. When mixed with water at the proper concentration and applied under pressure, the resulting solution can:

  • Kill mold, mildew, algae and bacteria
  • Whiten and brighten surfaces
  • Remove tough stains and discoloration
  • Deodorize musty areas
  • Help control future mold/mildew growth

The key is using the correct ratio that maximizes cleaning ability without risking damage to your home’s exterior.

What is the Best Bleach to Water Ratio for Mixing a Pressure Wash Solution?

The optimal bleach to water ratio can vary based on several factors:

  • Type of Surface – Some materials like wood, brick and painted surfaces need a milder bleach solution than more durable surfaces like concrete.
  • Level of Grime – Heavily soiled areas may need a stronger mix compared to lighter cleaning jobs.
  • Pressure Washer Settings – Higher pressure and flow rates allow you to use more diluted solutions.
  • Bleach Concentration – Household bleach contains ~6% sodium hypochlorite, while commercial-grade bleach may be 10-12.5% for increased strength.

As a general guideline, a mix ratio between 1:10 and 1:20 bleach to water is a safe starting point for most exterior house washing tasks. This equals:

  • 1 part bleach to 10 parts water
  • Or 1 part bleach to 20 parts water

So for example, 1 quart of bleach combined with 10-20 quarts of water. We’ll provide more precise mixing instructions later in this article.

Start with a 1:20 solution first and increase bleach concentration gradually if needed. It’s better to mix a weaker batch first and then make it stronger.

Mixing a 1:10 Bleach to Water Pressure Wash Solution

Here are two easy methods to mix a 1:10 ratio pressure wash solution:

For a 1-Gallon Batch:

  • Add 1 cup of bleach
  • Fill bucket with 10 cups of water
  • Mix well before pouring into pressure washer tank

For a 5-Gallon Batch:

  • Add 2 quarts of bleach
  • Fill pressure washer tank with 4 gallons of water
  • Mix thoroughly by running the pressure washer with the tank full

Adjust measurements appropriately to make larger or smaller batches.

Mixing a 1:20 Bleach to Water Pressure Wash Solution

To mix a weaker 1:20 bleach solution:

For a 1-Gallon Batch:

  • Add 1/2 cup bleach
  • Fill bucket with 10 cups of water
  • Mix completely before transferring to pressure washer

For a 5-Gallon Batch:

  • Add 1 quart bleach
  • Fill tank with 5 gallons of water
  • Mix by running pressure washer

Tips for Mixing and Applying Your Bleach Wash Solution

  • Always add bleach to water – never the other way around. This prevents bleach splashes.
  • Check bleach bottle for exact concentration percentage and adjust ratios accordingly.
  • Wear gloves, eye protection and cover bare skin – bleach can irritate.
  • Mix in a bucket first before pouring into pressure washer tank.
  • Mix a fresh batch daily – bleach concentration decreases over time.
  • Apply bleach solution from top to bottom of surface and rinse thoroughly.
  • If using on plants/landscaping, test a small area first and rinse immediately.

Cleaning Different Exterior Surfaces with Bleach Mixes

Below are some recommended bleach ratios for common exterior surfaces:

Vinyl Siding:

  • Start with a 1:20 bleach to water ratio
  • Monitor closely and rinse often to avoid damage

Wood Siding:

  • Use a very mild 1:50 bleach/water solution
  • Rinse thoroughly – bleach can discolor wood over time

Concrete and Brick:

  • A 1:10 bleach to water mix works well
  • Increase strength for heavily stained areas

Painted Surfaces:

  • Start with 1:20 mix and adjust as needed
  • Test a small spot first to check for compatibility

Roof Shingles:

  • Use a 1:50 ratio or milder
  • Bleach may strip color from shingles over time


  • Try a 1:10 bleach/water mix
  • Rinse immediately to prevent wood discoloration

Always start with a weaker mix first and gradually increase bleach concentration as needed. Monitor surfaces closely and rinse thoroughly after application.

Pressure Washers and Bleach Injectors

Many pressure washers come equipped with a downstream bleach injector or injection system. This allows you to independently control the amount of bleach being mixed into the pressurized water stream.

Follow manufacturer’s instructions for proper setup and calibration. Start with a weaker bleach concentration and slowly increase until optimal cleaning results are achieved.

Using an injector prevents the need to premix solutions and gives you better control over bleach amounts during cleaning. It also helps preserve full bleach strength compared to premixed batches.

Safely Storing and Disposing Leftover Bleach Mixes

Here are some tips for handling leftover bleach solutions:

  • Store any unused premixed solution in sealed containers out of sunlight. Sunlight degrades bleach over time.
  • Leftover diluted bleach solution will start losing disinfecting ability within hours to days. Mix fresh batches daily if possible.
  • Do not pour leftover bleach mix down drains. It can harm septic systems.
  • Allow bleach water to fully neutralize in open buckets for 24-48 hours before pouring onto grass areas for disposal. Rinse the area afterward.
  • Use test strips to verify bleach concentration is zero before disposal.

Properly handling bleach storage, application and disposal helps ensure safe and effective use around your home.

The Takeaway on Bleach to Water Ratios for Pressure Washing

Adding the right amount of bleach to your pressure washer’s tank can significantly boost exterior cleaning performance. Follow these guidelines when mixing bleach solutions:

  • Start with a weaker 1:20 bleach to water ratio and gradually increase strength as needed
  • Mix bleach in a bucket first before adding to pressure washer tank
  • Use bleach injectors for more precise control over concentration
  • Monitor surfaces closely and rinse immediately after cleaning
  • Adjust ratios based on surface type, soiling level and washer settings
  • Handle bleach safely by wearing gloves, eye protection and protective clothing

With the proper bleach to water mixing techniques, you can tackle even the toughest outdoor cleaning jobs. Always test on a small area first and find the optimal ratio for your specific pressure washing needs.

If you need help pressure washing the exterior of your home around Dawsonville Georgia, you can contact Sullins Suds Pressure Washing today!

Don’t Stop Here

More To Explore
How To Pressure Wash a Rug
How To Pressure Wash a Rug: Washing, Drying, and Maintaining

Pressure washing a rug requires careful attention to detail to avoid damaging delicate fibers. Follow these steps for optimal results:
1. Preparation
2. Choose the Right Pressure Washer
3. Detergent Selection
4. Test Spot
5. Even Application
6. Rinse Thoroughly
7. Allow to Dry

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