Some might say chlorine and bleach work the same in pressure washing their concrete floor. But after doing the process and choosing their preferred cleaning agent, they noticed some mold, dirt, and residue are still there. Knowing what chemicals to use in pressure washing is important to have a good finish and to avoid damaging your properties.

This guide will help you to determine the difference between using chlorine and bleach as a solution for pressure washing any surface based on different factors.

Pressure Washing with Chlorine

You can eliminate a lot more bacteria by pressure washing a surface with chlorine than using bleach. You will get a clean makeover of your backyard floor in no time. However, you should be aware of chlorine’s sensitivity to sunlight, as the light will disperse the chlorine and degrade its cleaning capabilities. Most chlorine solutions are mixed with a stabilizer to reduce this effect of light sensitivity.

Today’s Homeowner Tips

Chlorine is an efficient cleaning solution when using a pressure washer to clean any concrete surface. It can be used to remove moss from a concrete sidewalk or driveway. It can also aid in removing residue from leaked fuel in your driveway.

Here are the recommended steps to pressure wash any surface:

  1. Pressure wash the surface with water only. This technique is mostly used by cleaning services to effectively achieve the desired finish.
  2. Mix ¼ gallon of chlorine and 1 gallon of water for a more concentrated solution. You can also try the recommended ratio for the chlorine and water mixture, which is 1:9.
  3. Apply the chlorine to the surface by a pressure pump.
  4. Let it sit for 25 to 30 minutes.
  5. Pressure wash the surface with water.

Spot treat the part that needs more attention by redoing the steps mentioned above.

Pressure Washing with Bleach

One of the most common reasons people use bleach to clean their properties is because it is less expensive to purchase than chlorine solutions. 

Do the following steps to clean any surface by pressure washing it with bleach:

  1. Pressure wash the surface with water only.
  2. Mix ¼ gallon of bleach and 1 gallon of water.
  3. Apply the bleach on the surface by a pressure pump.
  4. Let it sit for 15 to 30 minutes.
  5. Pressure wash the surface with water and rinse it again if necessary.


Here are some reminders in using the bleach-water mixture to pressure wash any surfaces.

  • Bleach can destroy a wooden deck. Sensitive surfaces such as wood and marble cannot be pressure cleaned with bleach because bleach makes the hardwood more susceptible to mold and internally damage the structure of marbles.
  • Bleach is a very reactive substance. Bleach corrodes metal and ruins the color of your clothes. When used with other cleaning agents, they can generate chemical reactions that cause harm to both living and nonliving things. It can potentially damage your pressure washer’s rubber seals, rings, hoses, and pump.
  • Bleach is harmful and abrasive. A lot of house owners who pressure wash their backyard with bleach are having problems with their vegetation because the cleaning agent was also being absorbed by the nearby plants. To avoid this situation, try to over hydrate your plants before cleaning the backyard with bleach.

Chlorine vs. Bleach Solution

Let’s compare these solutions based on different factors to determine what cleaning agents work best for your application.

Most homeowners can clean their 4 x 3 m concrete floor within an hour by pressure washing it with a 1:4 ratio of water and chlorine mixture. While people who use bleach for pressure washing the same space of concrete floor spend an average of 1 to 2 hours to finish the job.

If you want to spot treat some areas or target specific irregularities on any surface of your house, choose a solution that is intended for that purpose.

Chlorine works best to remove or reduce the appearance of:

  • Irregular gradient lines
  • Residue and dark spots
  • Hardened small debris
  • Tough grimes
  • Stains on concrete

It is recommended to pressure wash the following areas with bleach.

  • Concrete driveway with molds and dried fuel residue
  • Pool surface with molds and hardened small debris
  • Stains on the patio, sidewalk of a pool, and roof surface

For small sections of moss on the side of a wall or concrete ground, pressure washing with water is enough. On the other hand,  pressure washing it with bleach can help prevent the moss from growing back. If you’re disinfecting a place that’s been exposed to bodily fluids and viruses, sanitize it by pressure washing it with a bleach-water mixture.

Chlorine can damage the lungs, resulting in various breathing difficulties if exposed frequently. Bleach is a harmful substance that can discolor, dry out, and destroy the surface of metal gutters, discolor painted areas, kill vegetation, and cause health issues to your children and animals if used incorrectly.

Any of these chemicals can cause a 2nd to 3rd degree burn with substantial pain, inflammation, blisters, or more severe skin damage if they come into contact with your skin. It is best to wear rubber or chemical resistant gloves, eye-protective gear, pants, long sleeves, and rubber boots.

Overall Impression: Which Solution is Better?

The base compound of bleach and chlorine is Sodium Hypochlorite. Household bleach, on the other hand, has additional chemicals and more active ingredients, making it a more aggressive solution.

Pressure washing a house with bleach is a good approach to get rid of mold, moss, and substantial dirt. On the other hand,  Chlorine is an excellent choice for removing oil stains from concrete floors. To avoid long-term damage, chlorine is ideal if you plan to pressure wash your backyard floor or driveway on your own.

For people with a large pool area and who have a lot of germs to get rid of, chlorine is the best option. If you wish to spot treat any stubborn stains, pressure wash an area with bleach.

Whether you pressure wash an area with a chlorine or bleach solution, the result depends on your application and the mixture. To effectively clean an area and to avoid damaging the surface and nearby properties, the appropriate amount of chemical agents must be diluted with water.

Having the right chemicals will help you get your job done easily and effectively. Use this guide to know when to use chlorine and bleach for pressure washing any surface to achieve the desired result.

Editorial Contributors
avatar for Matt Greenfield

Matt Greenfield

Matt Greenfield is an experienced writer specializing in home improvement topics. He has a passion for educating and empowering homeowners to make informed decisions about their properties. Matt's writing focuses on a range of topics, including windows, flooring, HVAC, and construction materials. With a background in construction and home renovation, Matt is well-versed in the latest trends and techniques in the industry. His articles offer practical advice and expert insights that help readers tackle their home improvement projects with confidence. Whether you're a DIY enthusiast or a seasoned professional, Matt's writing is sure to provide valuable guidance and inspiration.

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