You are here » Home » Acid Washing: What You Need To Know!

Acid Washing: What You Need To Know!

Acid washing what you need to know. Picture of hydochloric acid.

If you have concrete floors or walls that need deep cleaning, acid washing might be the answer. This process is a powerful solution for getting rid of stubborn oil/grease stains, dirt, and grime. Here’s everything you need to know about acid washing concrete, its benefits, and what you should consider before starting.

Table of Contents:

  1. What is Acid Washing?
  2. Benefits of Acid Washing
  3. Types of Concrete Surfaces to Acid Wash
  4. Safety Precautions
  5. How to Acid Wash Concrete?
  6. Factors to Consider Before Acid Washing
  7. Acid Washing vs Pressure Washing
  8. Common Mistakes to Avoid During Acid Washing
  9. Alternative Methods for Cleaning Concrete
  10. Professional Acid Washing Services
  11. Maintaining Acid-washed Concrete Surfaces
  12. Acid Washing Equipment and Supplies
  13. Environmental Impact of Acid Washing
  14. Acid Washing for Industrial Applications
  15. FAQ

What is Acid Washing?

Acid washing is a process that uses a mixture of water and muriatic acid (hydrochloric acid) to remove oil and grease stains, dirt, and grime from concrete surfaces. The acid solution is applied to the surface with a water can, then scrubbed with a stiff brush or broom, and then rinsed off with water. This process is very effective in removing tough stains, such as oil, grease, and mineral deposits.

Benefits of Acid Washing

Acid washing has many benefits, including:

  1. Deep cleaning: Acid washing can remove oil, grease dirt, grime, and stains that are deeply embedded in the concrete surface.
  2. No damage to the surface: Unlike other cleaning methods, acid washing doesn’t damage the surface of the concrete. Instead, it removes the top layer of dirt and stains, revealing a clean surface underneath.
  3. Cost-effective: Acid washing is a cost-effective way to clean large concrete surfaces, such as driveways, patios, and garage floors.
  4. Preparing the surface for coatings: Acid washing prepares the concrete surface for coatings such as paint, epoxy, or sealers.
  5. Long-lasting results: Acid washing provides long-lasting results, making it a cheap and efficient cleaning solution.

Types of Concrete Surfaces to Acid Wash

Acid washing should be used on bare concrete surfaces only. Surfaces that have been painted or sealed should not be acid washed. Acid washing is ideal for concrete driveways, patios, garage floors, and plain concrete surfaces.

Safety Precautions

Safety should be a top priority when acid washing concrete surfaces. Here are some precautions to keep in mind:

  1. Wear protective gear: A face mask, gloves, goggles, and protective clothing should be worn to avoid skin and eye irritation.
  2. Proper ventilation: Ensure that there is adequate ventilation in the area where you are acid washing.
  3. Keep away from children and pets: Keep the acid solution and all equipment away from children and pets.
  4. Dispose of acid properly: The acid solution should be disposed of properly by following local regulations.

How to Acid Wash Concrete?

Here are the steps to acid wash concrete:

  1. Prepare the area: Remove any furniture, plants, and debris from the area to be cleaned.
  2. Protect surrounding areas: Cover any surrounding areas with plastic or a tarp to protect them from the acid solution.
  3. Mix the acid solution: Mix one part muriatic acid with four parts water in a watering can.
  4. Apply the acid solution: Use the watering can to apply the acid solution onto the surface evenly. Allow it to sit for 5-10 minutes.
  5. Scrub the surface: Use a brush or broom to scrub the surface, paying attention to areas with tough stains.
  6. Rinse the surface: Rinse the surface thoroughly with water.

Factors to Consider Before Acid Washing

Before you decide to acid wash your concrete, there are a few factors to consider:

  1. Age and condition of the concrete: Acid washing is most effective on newer concrete surfaces. Older, worn-out concrete may not respond as well to acid washing.
  2. Weather conditions: Acid washing should be done on a dry day with moderate temperatures. Extreme heat or cold can affect the effectiveness of the process.
  3. Surface porosity: Acid washing is most effective on porous concrete surfaces. If your concrete is very smooth or polished, acid washing may not be as effective.
  4. Personal safety: Consider your own safety and whether you have the necessary protective gear and knowledge to undertake acid washing.

Acid Washing vs Pressure Washing

While both acid washing and pressure washing can clean concrete surfaces, there are some key differences:

  1. Cleaning method: Acid washing uses a chemical reaction to break down stains, while pressure washing uses high-pressure water to remove dirt and grime.
  2. Stain removal: Acid washing is more effective in removing tough stains, such as oil, rust, and mineral deposits, while pressure washing is better for general cleaning.
  3. If done correctly, acid washing does not damage the surface of the concrete, while applying too much pressure during pressure washing can potentially cause damage.
  4. Acid washing is recommended for bare concrete surfaces, while pressure washing can be used on a variety of surfaces, including painted or sealed ones.

Common Mistakes to Avoid During Acid Washing

To ensure successful acid washing, here are some common mistakes to avoid:

  1. Overusing or under-using acid: Using too much acid can damage the concrete, while using too little may not effectively clean the surface.
  2. Failing to neutralize the acid: After the acid washing process, it is crucial to neutralize any remaining acid on the surface by rinsing it thoroughly with water.
  3. Ignoring safety precautions: Always prioritize safety by wearing protective gear, ensuring proper ventilation, and following disposal guidelines.
  4. Skipping surface preparation: Properly preparing the concrete surface by removing debris and protecting surrounding areas is essential for a successful acid wash.

Alternative Methods for Cleaning Concrete

If acid washing is not suitable for your concrete surface, there are alternative cleaning methods available:

  1. Pressure washing: Using high-pressure water can effectively remove dirt and grime from concrete surfaces.
  2. Steam cleaning: Steam cleaning utilizes high-temperature steam to dissolve and remove tough stains and dirt from concrete.
  3. Chemical cleaners: There are specific chemical cleaners available that can target and remove different types of stains from concrete surfaces.
  4. Mechanical scrubbing: Using a mechanical scrubber or floor buffer with appropriate cleaning solutions can provide a thorough clean for your concrete.

Professional Acid Washing Services

While acid washing can be done as a DIY project, it is advisable to hire professional services like Pressure Washed South East QLD for optimal results. Professional technicians have the experience, equipment, and knowledge to safely and efficiently acid wash your concrete surfaces, saving you time and ensuring a high-quality clean.


Image displaying Apartment complex, Commercial Car park and driveway. All have been pressure cleaned by Pressure Washed South East QLD

Maintaining Acid-washed Concrete Surfaces

To keep your acid-washed concrete surfaces looking their best and to extend their lifespan, here are some maintenance tips to follow:

  1. Regular cleaning: Regularly sweep or rinse the surface to remove dirt and debris that can build up over time.
  2. Avoid harsh chemicals: Avoid using harsh chemicals or cleaning agents that could damage the acid-washed surface.
  3. Apply sealant: Applying a sealant can help protect the acid-washed surface and extend its lifespan.
  4. Fix any damage: Repair any cracks or damage to the concrete surface as soon as possible to prevent further deterioration.

Acid Washing Equipment and Supplies

If you decide to perform acid washing yourself, you will need the following equipment and supplies:

  1. Protective gear: Wear a face mask, gloves, goggles, and protective clothing to protect yourself from the acid solution.
  2. Sprayer: Use a sprayer to evenly apply the acid solution onto the concrete surface.
  3. Brush or broom: Use a brush or broom with stiff bristles to scrub the surface and remove stains.
  4. Plastic container: Mix the acid solution in a plastic container to ensure the safety of the solution and prevent any reactions with other materials.

Environmental Impact of Acid Washing

It is important to consider the environmental impact of acid washing. The acid solution and rinsed-off residue should be properly collected and disposed of according to local regulations to prevent contamination of the environment. Choose environmentally friendly products whenever possible and follow all safety practices to minimize environmental harm.

Acid Washing for Industrial Applications

Acid washing is not limited to residential use but also finds applications in various industrial settings. From warehouses to factories, acid washing can effectively clean and prepare concrete surfaces for various industrial processes. Consult with professionals like Pressure Washed South East QLD for customized industrial acid washing services.


Image displaying Apartment complex, Commercial Car park and driveway. All have been pressure cleaned by Pressure Washed South East QLD


  1. What is acid washing?

It’s a process that involves removing the top layer off a concrete surface to open its pores and provide a clean slate for applying a coating or to remove tough stains.

  1. What are some reasons for acid washing a surface?

The process of acid washing removes laitance and contaminants that do not wash away with water and soap, and also provides a clean surface for a coating to adhere to.

  1. What is the difference between acid washing and acid staining?

Acid washing is used to prepare a concrete surface for a coating, while acid staining involves using a stain to penetrate the surface of your concrete to give it a specific color or colors.

  1. How do I protect myself during an acid wash?

It is important to use protective gear such as gloves, a mask, goggles, and coveralls to protect yourself from acid splashing.

  1. How do I protect nearby plants during an acid wash?

Plants should be covered to avoid contact with the acid solution, as it could harm or kill them.

  1. What is the proper acid solution to use for an acid wash?

Check the recommend solution for the acid you have. Usually, the acid solution should be mixed with 1 part acid to 4 parts water, poured slowly onto the surface, and then neutralized with a baking soda solution.

  1. How long do I leave the acid solution on the surface?

The acid solution should only be left on the surface until it stops fizzing, after which it should be neutralized with a baking soda solution.

  1. How do I neutralize the acid solution.

A baking soda solution should be mixed with 20 litres of water for every 200grams of baking soda and distributed on the surface to neutralize the acid.

  1. What is the proper technique for pressure washing an acid washed surface?

3,000 PSI at 4 gallons a minute, using a fan tip, is recommended to pressure wash an acid washed surface.

  1. What can happen if the acid isn’t neutralized completely?

If the acid is not completely neutralized, it can gradually weaken the strength of the concrete over time.

  1. Can acid washing be dangerous?

Yes, using acid is dangerous if not handled properly, posing risks of chemical burns and acid inhalation.

  1. Is acid washing always the best option for preparing a concrete surface for coating?

No, in many cases, grinding a surface is just as effective for cleaning and opening pores to accept a coating, paint, or water-based stain.

  1. Can acid washing make a surface too porous?

Yes, acid washing a surface can make it too porous.

  1. Can acid harm nearby plants?

Yes, acid can harm nearby plants if it gets on them, so if you’re attempting to acid wash a concrete patio or surface, you need to be mindful of this. It can also harm the environment if the run enters water ways.

  1. When should I use acid washing?

Acid washing is only recommended when grinding the surface is not possible and tough stains such as oil and grease cannot be removed using safer methods.


Acid washing is a powerful cleaning solution for concrete surfaces, providing deep cleaning and long-lasting results. Whether you choose to tackle it yourself or hire professional services like Pressure Washed South East QLD, acid washing can restore the beauty and cleanliness of your concrete floors, driveways, patios, and more.

Consider the factors, follow safety precautions, and evaluate alternative cleaning methods to make the best decision for your concrete cleaning needs. For exceptional results and peace of mind, contact Pressure Washed South East QLD at 0487 000 328 and experience the expertise and professionalism of their dedicated team.


Add for professional exterior cleaning. In the back ground is the team from pressure washed south east qld pressure cleaning


Arrange a Quote


Contact us today for a powerful external clean.