What to Spray on Concrete before Pressure Washing [2023 Updated]

If you’re planning to pressure wash your concrete surfaces, you might be wondering what to spray on them beforehand to achieve the best results. Perhaps you’ve tried pressure washing your concrete without prepping it, only to find the results less than satisfactory. Or maybe you’re just starting out and want to ensure that you’re doing everything right. 

What to Spray on Concrete before Pressure Washing? Before pressure washing concrete, it’s recommended to spray a degreaser or a concrete cleaner onto the surface. These products help to break down and remove any built-up dirt, oil, or other contaminants that may be present, making it easier to achieve a thorough clean.

Whatever the case, this blog post will provide you with valuable insights on what to spray on concrete before pressure washing, so you can achieve optimal results and enjoy a cleaner, brighter surface.

Types of Pre-Treatment Solutions

Types of Pre-Treatment Solutions

When it comes to pressure washing concrete, pre-treatment is an essential step that shouldn’t be overlooked. The pre-treatment solution you use can make a big difference in the effectiveness of your pressure washing efforts.

Following are the different types of pre-treatment solutions you can use before pressure washing your concrete surfaces. From degreasers to rust removers, we will cover everything you need to know to choose the right pre-treatment solution for your concrete cleaning needs. 

Commercial concrete cleaners

In the context of pre-treatment solutions for pressure washing concrete, commercial concrete cleaners are an effective option. These cleaners are specifically designed to remove tough stains, dirt, and grime from concrete surfaces, making them ideal for prepping the surface before pressure washing.

They are available in a variety of formulations, including acidic, alkaline, and neutral pH levels, and can be used on both interior and exterior concrete surfaces. Carefully follow the manufacturer’s instructions for use and safety precautions when working with commercial concrete cleaners.

Bleach solutions

Bleach solutions are a common pre-treatment solution used before pressure washing concrete surfaces. They are effective in removing mildew, algae, and other stains from the surface. Dilute bleach solutions properly to prevent damage to the surface and ensure safety during application.

It is recommended to wear protective gear such as gloves and eye goggles when handling bleach solutions. Rinse the surface thoroughly after applying the bleach solution to prevent any residual bleach from causing damage or discoloration to the concrete surface.

Oxygenated bleach solutions

Oxygenated bleach solutions are a type of pre-treatment solution that can be used on concrete before pressure washing. These solutions contain hydrogen peroxide or sodium percarbonate, which helps to break down dirt, grime, and other contaminants on the surface of the concrete. They are effective in removing stains caused by mold, mildew, and algae.

Oxygenated bleach solutions are safe to use on concrete and are eco-friendly, as they break down into oxygen and water when they are used. They are also easy to use and require little preparation before application.

Vinegar solutions

Vinegar solutions are a popular and effective pre-treatment option for concrete before pressure washing. They are non-toxic, affordable, and readily available. Vinegar solutions work by breaking down dirt and grime on the concrete surface, making it easier to remove during pressure washing. To make a vinegar solution, mix equal parts of white vinegar and water.

For tougher stains, use a stronger concentration of vinegar. Note that vinegar can etch certain types of concrete surfaces, so it’s recommended to test a small area first before applying the solution to the entire surface. Vinegar solutions may not be effective for removing oil and grease stains on concrete.

Detergent-based cleaners

Detergent-based cleaners are one type of pre-treatment solution that can be used before pressure washing concrete surfaces. These cleaners are designed to break down and remove stubborn stains, dirt, and grime from the surface of the concrete.

They are usually mixed with water and applied to the surface before pressure washing, and can be effective in removing oil, grease, and other types of stains. Follow the manufacturer’s instructions and safety guidelines when using these cleaners, as they can be harmful to the environment and to human health if not used properly.

Step 1. Preparing the Concrete Surface

Step 1. Preparing the Concrete Surface

Following are the steps you need to take to prepare your concrete surface before pressure washing, so you can achieve the best possible results. 

Clearing debris

Before pressure washing concrete, also clear any debris from the surface. This includes items such as loose rocks, sticks, and leaves, as well as any dirt or dust that has accumulated on the surface.

Clearing debris ensures that the pressure washer can effectively clean the concrete surface without causing any damage or creating additional mess. It’s recommended to use a broom or leaf blower to clear the debris before beginning the pressure washing process.

Identifying and addressing stains

When pressure washing concrete, identify and address any stains on the surface beforehand. This ensures that the cleaning process is effective and efficient. Different types of stains may require different solutions, such as using a degreaser for oil stains or a bleach solution for mold and mildew. Choose the right solution and follow safety guidelines when applying it to the concrete surface.

Patching cracks and holes

Patching cracks and holes is a crucial step before pressure washing concrete. Any cracks or holes in the surface can trap water and cause damage during pressure washing. To patch cracks and holes, use a concrete patching compound and a trowel. Clean the area first with a wire brush and water.

Allow the patching compound to dry completely before pressure washing the surface. This will ensure that the concrete is fully repaired and the pressure washing will not cause any further damage.

Protecting nearby surfaces and plants

When pressure washing concrete surfaces, take steps to protect nearby surfaces and plants from damage. This can be done by covering adjacent surfaces with plastic sheeting or tarps and wetting down nearby plants before and after pressure washing.

By taking these precautions, you can ensure that the pressure washing process is effective without causing damage to surrounding areas.

Step 2. Applying the Pre-Treatment Solution

In the following paragraphs, we are discussing what pre-treatment solution is, why it’s important, and what options are available for you to use.

Choosing the right application method

When it comes to pre-treating concrete before pressure washing, choosing the right application method is crucial for achieving the desired results. Some common methods include using a garden sprayer, a pump sprayer, or a pressure washer with a low-pressure setting.

The choice of method will depend on various factors such as the size of the area to be treated, the type of pre-treatment solution being used, and the desired level of pressure for cleaning.

Properly diluting the solution

When applying a pre-treatment solution to concrete before pressure washing, properly dilute the solution to ensure it’s effective without causing damage. Follow the manufacturer’s instructions for dilution ratios and mix the solution thoroughly before applying it to the surface.

Use a measuring cup or other precise measuring tool to ensure accurate dilution. Applying an improperly diluted solution can result in uneven cleaning and potential damage to the concrete.

Allowing the solution to work

After applying the pre-treatment solution to the concrete surface, it’s essential to allow it to work for the recommended amount of time. Typically, the pre-treatment solution needs to sit on the surface for at least five to ten minutes before pressure washing. During this time, the solution breaks down the dirt, grime, and other contaminants on the concrete, making it easier to remove during the pressure washing process.

It’s crucial not to let the solution dry on the surface, as this can lead to streaking or staining. If the solution starts to dry, it’s best to add more solution or water to keep the surface moist. Once the recommended time has passed, rinse the surface thoroughly with water before starting the pressure washer. This will help to ensure a clean and effective pressure washing job.

Step 3. Pressure Washing the Concrete

Step 3. Pressure Washing the Concrete

Choosing the right pressure washer

When pressure washing concrete, it’s essential to choose the right pressure washer to get the job done efficiently. The pressure washer’s power and water flow rate are the two key factors to consider when selecting the right machine for the job.

A pressure washer with a higher PSI (pounds per square inch) rating will be able to remove more stubborn stains and dirt from concrete, while a higher water flow rate (measured in gallons per minute, or GPM) will help cover a larger surface area in less time. It’s also essential to choose the appropriate nozzle for the pressure washer, as this will determine the spray pattern and pressure.

A 25-degree nozzle is typically suitable for most concrete cleaning tasks. Be sure to wear protective gear when operating the pressure washer, such as safety glasses and boots, and follow the manufacturer’s instructions carefully.

Adjusting the pressure and nozzle settings

When pressure washing concrete, adjusting the pressure and nozzle settings is crucial for achieving the best results. Choose the appropriate nozzle based on the pressure washer’s power and the condition of the concrete surface.

The spray angle should also be considered, as a narrow spray angle will provide more concentrated pressure while a wider angle will cover a larger surface area. By properly adjusting these settings, you can effectively remove dirt, grime, and stains from your concrete surface without causing any damage.

Techniques for effective pressure washing

To effectively pressure wash concrete, there are a few techniques you should keep in mind. First, make sure to use the correct nozzle and pressure setting for the job. A nozzle with a fan spray pattern and a pressure of at least 3,000 PSI is recommended.

Next, start by pre-soaking the concrete with a cleaning solution to loosen dirt and grime. You can use a mixture of water and a mild detergent, or a specialized concrete cleaner. Let the solution sit for a few minutes before proceeding to pressure washing.

When pressure washing, keep the nozzle moving constantly to avoid leaving marks on the surface. Also, use a sweeping motion rather than aiming directly at the surface to prevent damage.

Rinse the concrete thoroughly with clean water and allow it to dry completely before applying any sealant or other coatings. By following these techniques, you can achieve an effective and thorough pressure washing of your concrete surfaces.

Rinsing and neutralizing the surface

In order to properly prepare concrete for pressure washing, rinse and neutralize the surface beforehand. This step involves thoroughly rinsing the concrete with water to remove any loose debris or dirt.

After rinsing, a neutralizing solution should be applied to the surface to balance the pH level and prevent any damage to the concrete. This step ensures that the concrete is clean and ready for effective pressure washing.

Step 4. Post-Pressure Washing Care

Step 4. Post-Pressure Washing Care

Below are some essential post-pressure washing care tips to help you maintain the cleanliness and integrity of your property.

Inspecting the concrete surface

When inspecting the concrete surface after pressure washing, look for any areas that may require further cleaning or treatment. Check for any remaining stains, mold or mildew growth, or areas where the surface may be damaged or uneven.

Address any issues before moving on to post-pressure washing care, such as applying a sealant or protective coating. By thoroughly inspecting the surface, you can ensure that the final result is a clean, even, and durable concrete surface.

Addressing any remaining stains

After pressure washing, there may still be some stains left on the surface. If this is the case, it is crucial to address them promptly. First, identify the type of stain to determine the appropriate treatment method. For example, oil stains may require a degreaser or a special cleaning solution, while rust stains may need a rust remover. Be careful not to use harsh chemicals or abrasive tools that could damage the surface.

Always follow the manufacturer’s instructions and take necessary safety precautions when using any cleaning products. If the stain is particularly stubborn or you are unsure how to treat it, it may be best to seek professional help to avoid causing further damage.

Sealing the concrete for future protection

Sealing the concrete after pressure washing is an essential step to protect the surface from future damage. Concrete is a porous material that can absorb water, oils, and other substances, leading to stains, cracks, and other issues over time.

Applying a concrete sealer creates a protective barrier that prevents water and other substances from penetrating the surface, making it easier to clean and maintaining its appearance for a longer time. There are different types of concrete sealers available, including acrylic, epoxy, and penetrating sealers. 

Safety Precautions

Safety Precautions

Following are some of the essential safety precautions that you need to keep in mind before you start pressure washing concrete. By following these precautions, you can ensure a successful and safe pressure washing experience.

Personal protective equipment (PPE)

When pressure washing concrete, also wear appropriate personal protective equipment (PPE) to ensure your safety. The pressure and water used in pressure washing can cause serious injuries if not used with caution. Some of the essential PPE include:

  1. Eye Protection: Safety goggles or a face shield must be worn to protect your eyes from flying debris, water, and chemicals.
  2. Respiratory Protection: A respirator must be worn to protect your lungs from inhaling dust and chemicals that may be released during pressure washing.
  3. Hand Protection: Rubber gloves should be worn to protect your hands from harsh chemicals and to maintain a firm grip on the pressure washer.
  4. Footwear: Wear closed-toe shoes with good grip soles to avoid slipping on wet surfaces and to protect your feet from injury.
  5. Protective Clothing: Wear long-sleeved shirts and pants made of thick and durable materials like denim or canvas to protect your skin

Proper ventilation

Proper ventilation is a crucial safety precaution when spraying chemicals on concrete before pressure washing. Good ventilation ensures that any harmful fumes or chemicals are properly dispersed, reducing the risk of respiratory problems or other health issues.

Work in an open and well-ventilated area, and to avoid working in enclosed or poorly ventilated spaces. If working indoors, it may be necessary to use fans or other ventilation equipment to ensure proper air flow.

By taking the necessary steps to ensure good ventilation, you can help protect your health and safety while pressure washing concrete.

Safe handling and storage of chemicals

When pressure washing concrete, take safety precautions, especially when handling and storing chemicals. Proper storage and handling of chemicals can prevent accidents and injuries. Always read the labels and follow instructions when using chemicals, wear appropriate protective gear, and store chemicals in a safe and secure location out of reach of children and pets.

Properly dispose of any unused chemicals and containers according to local regulations. By following these safety precautions, you can ensure a safe and successful pressure washing project.

Disposing of used solutions

When pressure washing concrete, to take safety precautions to avoid harm to yourself or the environment. Disposing of used solutions is a crucial aspect of this process, as many pressure washing solutions can contain chemicals that are harmful if not disposed of properly.

Follow local regulations for proper disposal, such as taking the used solution to a hazardous waste disposal facility or diluting it with water and disposing of it down the drain in accordance with local laws.

Improper disposal can lead to environmental contamination and potential health risks, so be sure to handle used pressure washing solutions with care.


To prepare concrete for pressure washing, apply a pre-treatment solution such as a concrete cleaner or degreaser. This will loosen and remove any surface dirt, grime, or oil, and help your pressure washer achieve a deeper clean. Always follow the manufacturer’s instructions for the best results.

As a homeowner or property manager, you want to ensure that your concrete surfaces look their best and are well-maintained. Pressure washing is a great way to clean and remove dirt, grime, and other stains from your concrete surfaces. Before you start pressure washing, it’s important to properly pre-treat the surface to achieve the best results. 

Frequently Asked Questions (What to Spray on Concrete before Pressure Washing)

What chemical to spray on concrete before pressure washing?

Before pressure washing concrete, it is common to use a chemical cleaner to pre-treat the surface. One commonly used chemical is a concrete cleaner or degreaser. These cleaners are specifically formulated to remove stains, dirt, grease, and other contaminants from the concrete surface, making it easier to clean during the pressure washing process.

It is important to follow the manufacturer’s instructions when using any chemical cleaner and ensure proper safety precautions are taken.

How do you pre-treat concrete before pressure washing?

To pre-treat concrete before pressure washing, start by removing loose debris and sweeping the area clean. Then, wet the concrete surface with water to ensure it is thoroughly saturated. Next, apply a concrete cleaner or degreaser according to the manufacturer’s instructions.

Allow the cleaner to dwell on the surface for the recommended time, typically a few minutes. Use a scrub brush or broom to agitate the cleaner and loosen any stains or dirt. Finally, rinse the concrete surface thoroughly with clean water before proceeding with pressure washing.

Should you treat concrete before pressure washing?

Treating concrete before pressure washing is generally recommended for optimal cleaning results. Pre-treating the surface helps to remove stains, dirt, grease, and other contaminants, making the pressure washing process more effective. Chemical cleaners or degreasers designed for concrete can help break down and lift stubborn stains and grime.

However, it is essential to follow the manufacturer’s instructions, take necessary safety precautions, and ensure proper rinsing to avoid any potential damage to the concrete surface.

What is the best solution for pressure washing concrete?

When pressure washing concrete, there are several solutions that can be effective. A common approach is to use a mixture of water and a concrete cleaner or degreaser. These solutions are specifically formulated to tackle stains, dirt, grease, and other contaminants commonly found on concrete surfaces.

Additionally, for particularly stubborn stains, you may need to use specialized concrete stain removers or solvents. It is crucial to choose a solution that is appropriate for the specific cleaning needs and follow the manufacturer’s instructions for best results.

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Andrew Joseph
Andrew Joseph

Introducing Andrew Joseph, a pressure washing expert with 15 years of experience in residential, commercial, and industrial projects. Andrew shares his vast knowledge through insightful blog posts, offering valuable tips and best practices for optimal cleaning results. His passion for educating others, combined with his extensive expertise, makes Andrew an indispensable resource for those looking to master the art of pressure washing.