What Chemicals do you Use to Pressure Wash a House [2023 Updated]

Have you ever noticed that over time, the exterior of your home starts to look dull and dingy? It’s not uncommon for dirt, grime, and even mold and mildew to accumulate on the siding and other surfaces. Pressure washing is an effective solution to bring your home back to its former glory, but what chemicals should you use? This question may have crossed your mind if you’re considering pressure washing your house.

What Chemicals do you Use to Pressure Wash a House? When pressure washing a house, it’s important to use environmentally friendly chemicals to minimize harm. Opt for biodegradable solutions such as oxygen bleach or mild detergents, which effectively remove dirt, mold, and mildew without causing harm to plants, pets, or the ecosystem.

In this blog, we’ll explore the chemicals commonly used in pressure washing and how to use them safely to get the best results.

Types of Chemicals for Pressure Washing

Types of Chemicals for Pressure Washing

Here are the different types of chemicals that are commonly used for pressure washing and their specific uses, so you can make an informed decision on which one to use for your particular cleaning needs. From detergents to degreasers, we’ll cover everything you need to know to get your house looking clean and fresh. So, let’s dive in!

Bleach-based solutions

Bleach-based solutions are a common type of chemical used for pressure washing houses. These solutions typically contain a mixture of bleach, water, and sometimes other cleaning agents. Bleach-based solutions are effective for removing dirt, grime, and mildew from surfaces like siding, decks, and fences.

They can be harsh and potentially damage surfaces if not used properly. It’s important to follow the manufacturer’s instructions and take necessary safety precautions when using bleach-based solutions for pressure washing.

Sodium hypochlorite

Sodium hypochlorite is a common chemical used for pressure washing houses. It is also known as bleach and is a powerful disinfectant and cleaner. When used in pressure washing, it can effectively remove dirt, grime, and mold from surfaces.

It should be used with caution as it can damage certain materials and cause harm to plants and animals. It is important to follow proper safety measures when using sodium hypochlorite for pressure washing.

Trisodium phosphate

Trisodium phosphate (TSP) is a commonly used chemical in pressure washing. It is an effective degreaser and cleaning agent that can remove tough stains, dirt, and grime from various surfaces, including house sidings.

TSP can be harmful to plants and the environment, and it should be used with caution. It is recommended to dilute TSP before use and to avoid letting it come into contact with plants and vegetation.

Sodium hydroxide

Sodium hydroxide, also known as lye or caustic soda, is a strong alkaline chemical used in pressure washing to remove stubborn stains and dirt from surfaces such as concrete, brick, and metal. It is often used in a solution with water and other cleaning agents to enhance its effectiveness.

However, handle sodium hydroxide with care as it can be corrosive and cause skin irritation or chemical burns. Protective gear such as gloves and goggles should be worn when using it. Sodium hydroxide should not be used on delicate surfaces such as wood or painted surfaces as it can cause damage.

Non-toxic, biodegradable alternatives

This section of the content will focus on non-toxic and biodegradable alternatives for pressure washing chemicals. These alternatives are becoming more popular due to their environmentally friendly nature and the reduced risk of harm to humans and animals. Some examples of non-toxic and biodegradable alternatives include vinegar, baking soda, and citrus-based cleaners.

These options are effective for removing dirt, grime, and mildew from a home’s exterior without causing harm to the environment or the homeowner.

Choosing the Right Chemicals

Choosing the Right Chemicals

Below are the various types of chemicals that are commonly used for pressure washing and provide guidance on how to select the right one for your specific needs.

Evaluating surface materials

When pressure washing a house, consider the surface materials to determine which chemicals can be safely used. Different materials such as wood, brick, and vinyl siding may require specific chemicals to avoid damage. It’s essential to evaluate the surface materials beforehand to select the appropriate chemicals for the job. Using the wrong chemicals can lead to discoloration, corrosion, and other forms of damage that can be costly to repair. Therefore, it’s crucial to identify the surface material before selecting the chemical to use for pressure washing.

Assessing the level of dirt and grime

When pressure washing a house, assess the level of dirt and grime on the surfaces to determine the appropriate chemicals needed for the job. This step is crucial because using the wrong chemicals can damage the surface being cleaned or fail to remove all the dirt and grime. Therefore, evaluate the condition of the surfaces before selecting the appropriate chemicals for pressure washing.

Environmental and safety considerations

When pressure washing a house, consider the potential environmental and safety impacts of the chemicals you use. Chemicals can end up in the soil, waterways, and air, harming plants and animals. Some chemicals can pose health risks to humans, especially if they are inhaled or come into contact with the skin.

To minimize these risks, choose chemicals that are environmentally friendly and safe for use around people and pets. Look for biodegradable, non-toxic options that are specifically designed for pressure washing and follow all safety precautions when using them.

Preparing the Chemical Solution

Preparing the Chemical Solution

Following are the steps involved in preparing the chemical solution for pressure washing your house. By following these steps, you can ensure that you’re using the right chemicals in the right proportions for a thorough and safe cleaning.

Dilution ratios for different chemicals

In pressure washing a house, prepare a chemical solution that is effective in removing dirt, grime, and other tough stains. Dilution ratios for different chemicals are important to consider to ensure that the solution is safe to use and doesn’t cause any damage to the surfaces being cleaned.

It’s crucial to follow the manufacturer’s instructions for dilution ratios as using too much chemical can be harmful to the environment and too little may not be effective in removing stains. Some commonly used chemicals for pressure washing include bleach, sodium hydroxide, and phosphoric acid, each with their own recommended dilution ratios.

Adding surfactants for improved effectiveness

When pressure washing a house, adding surfactants to the chemical solution can greatly improve the effectiveness of the cleaning process. Surfactants are chemicals that help break down dirt and grime, making it easier to remove with the pressure washer. Some commonly used surfactants include detergents, soaps, and degreasers.

Choose the right type and amount of surfactant based on the surface being cleaned and the level of dirt buildup. It is recommended to follow the manufacturer’s instructions when mixing the chemical solution to ensure safe and effective use.

Mixing guidelines

When preparing a chemical solution for a pressure washer, it is essential to follow certain guidelines to ensure safety and effectiveness. Here are some general mixing guidelines to consider:

  • Read the manufacturer’s instructions: Always start by reading the instructions provided by the chemical manufacturer. They will typically provide specific guidelines on dilution ratios and usage recommendations for their product.
  • Wear protective gear: Before handling any chemicals, put on protective gear such as gloves, goggles, and a face mask to protect yourself from potential splashes or fumes.
  • Dilution ratios: Chemical solutions used in pressure washers are typically diluted with water. The dilution ratio will depend on the specific chemical and the desired strength. Follow the manufacturer’s instructions to determine the appropriate ratio. It is crucial not to exceed the recommended concentration, as this could damage surfaces or equipment.
  • Mixing container: Select an appropriate mixing container that is large enough to hold the desired volume of solution. Make sure it is clean and free from any residues of other chemicals.
  • Water temperature: Pay attention to the water temperature recommended by the manufacturer. Some chemicals may require warm or hot water for optimal dilution and effectiveness.
  • Gradual mixing: Start by filling the mixing container with the required amount of water. Then, slowly add the chemical concentrate while stirring or agitating the solution. This gradual mixing helps prevent splashing and allows for proper dispersion of the chemical.
  • Mixing tools: Use a suitable mixing tool, such as a stir stick or paddle, to thoroughly mix the solution. Avoid using reactive materials such as metal tools that may interact with certain chemicals.
  • Dissolving time: Some chemicals may take time to dissolve completely in water. Follow the manufacturer’s instructions regarding the recommended dissolving time and ensure that the solution is well-mixed before use.
  • Precautions for hazardous chemicals: If you are working with hazardous chemicals, such as acids or strong detergents, take extra precautions. Work in a well-ventilated area, avoid inhaling fumes, and handle the chemicals with care.
  • Labeling and storage: Once the solution is prepared, label the container with the name of the chemical, the date of preparation, and any relevant safety information. Store the solution in a secure location away from children, pets, and incompatible materials.

Proper Application of Chemicals

Here is the proper application of chemicals for pressure washing your house, including the types of chemicals you can use and how to apply them safely and effectively.

Preparing the surface for pressure washing

Preparing the surface for pressure washing is an essential step to ensure effective and safe cleaning. It involves removing any loose debris or dirt from the surface and applying a cleaning solution to break down stubborn stains and dirt. Prior to pressure washing, protect any delicate surfaces and nearby vegetation by covering them with plastic sheeting or wetting them down with water.

It is also crucial to choose the right cleaning solution for the surface being cleaned and to follow the manufacturer’s instructions carefully to avoid damage to the surface or harm to the environment.

Diluting and mixing chemicals

When pressure washing a house, it’s essential to dilute and mix chemicals properly to ensure their effectiveness and safety. Diluting chemicals means adding water to them, which lowers their concentration and makes them less potent. When mixing chemicals, follow the manufacturer’s instructions and use the recommended proportions to avoid damaging the surfaces being cleaned or harming the environment.

It’s also recommended to wear protective gear, such as gloves and goggles, when handling chemicals. Properly diluting and mixing chemicals can ensure that your pressure washing job is done safely and effectively.

Applying chemicals with the correct pressure washer settings

The correct pressure washer settings are crucial when applying chemicals during a house pressure washing. Using too high a pressure can damage the surface, while too low pressure won’t clean the surface effectively.

Follow the manufacturer’s instructions and dilute the chemicals properly. It’s also recommended to test a small area first and adjust the pressure and chemical concentration as necessary. Applying chemicals with the correct pressure washer settings will ensure a thorough and safe cleaning of the house.

Rinsing and neutralizing the treated area

After applying chemicals during pressure washing, it is crucial to rinse and neutralize the treated area properly. Rinsing the area thoroughly with clean water helps to remove any remaining chemicals, dirt, or debris. Neutralizing the surface with a neutralizing solution or water can help prevent any damage to the surface or harm to the environment.

Neglecting to rinse and neutralize the surface can result in chemical residue buildup and potential damage to the surface or harm to the environment. Therefore, rinsing and neutralizing are important steps in the pressure washing process.

Tips for Effective Pressure Washing

Tips for Effective Pressure Washing

Below are some tips for effective pressure washing, including what chemicals to use to ensure that your home looks its best after a good cleaning.

Choosing the right pressure washer nozzle

When it comes to pressure washing a house, choosing the right nozzle is crucial for achieving effective and efficient cleaning. Nozzles are available in different sizes and angles, which determine the pressure and the spread of water. Select the appropriate nozzle based on the surface you’re cleaning, as using the wrong nozzle can damage the surface or not clean it properly.

A 0-degree nozzle is the most powerful and should be used with caution, while a 40-degree nozzle is the gentlest and can be used for more delicate surfaces. Check the nozzle regularly for any signs of wear or damage and replace it as needed to ensure safe and effective cleaning.

Using proper technique to avoid damage

When pressure washing a house, use proper technique to avoid causing damage to the surface being cleaned. This includes using the appropriate pressure level and angle of the nozzle, starting at a low pressure and gradually increasing as needed, and keeping the nozzle moving to prevent concentrated pressure in one area. Be aware of any delicate areas, such as windows or wood siding, and use a lower pressure or different cleaning method to avoid causing damage.

Regular maintenance for optimum performance

Regular maintenance is crucial for maintaining the optimum performance of your pressure washer. This includes inspecting and cleaning the nozzle and spray gun regularly, checking and replacing any damaged or worn-out parts, and keeping the engine oil and air filter clean. By following a regular maintenance schedule, you can ensure that your pressure washer continues to function effectively and efficiently, and avoid any potential breakdowns or damage to your property.

Safety Precautions

Safety measures that you should keep in mind while pressure washing your house. By following these safety precautions, you can ensure that you are not only protecting yourself but also your property and the environment. So, before you start pressure washing your house, make sure to read through these safety tips carefully.

Personal protective equipment

When pressure washing a house, use personal protective equipment (PPE) to ensure your safety. PPE includes items such as eye protection, gloves, and appropriate footwear. Wear clothing that covers your skin to protect against chemical exposure. Using PPE can prevent injuries and minimize the risks associated with pressure washing chemicals.

Handling and storage of chemicals

When pressure washing a house, consider the handling and storage of the chemicals used. These chemicals can be hazardous if not handled properly, and can cause harm to both people and the environment. To ensure safety, it is recommended to wear protective gear such as gloves and goggles, and to store the chemicals in a safe, dry, and well-ventilated area away from heat sources and open flames. Properly label and dispose of any unused or expired chemicals.

Proper ventilation and outdoor usage

When pressure washing a house, take proper safety precautions, including ensuring proper ventilation and using the equipment outdoors. This helps prevent the inhalation of harmful chemicals and fumes, which can lead to respiratory issues and other health problems. Outdoor usage also reduces the risk of slipping and falling on wet surfaces, which can result in serious injuries. By taking these precautions, you can ensure that pressure washing your house is a safe and effective process.


When pressure washing a house, it’s common to use a cleaning solution that contains chemicals like sodium hypochlorite (bleach) or trisodium phosphate (TSP). These chemicals help to break down dirt, grime, and stains, leaving your home looking clean and fresh.

When it comes to pressure washing your house, choosing the right chemicals is crucial for achieving a clean and well-maintained home exterior. The use of chemicals can help to remove dirt, grime, and other stubborn stains from your home’s exterior surfaces. However, not all chemicals are created equal, and using the wrong ones can cause damage to your property and harm to the environment.

Frequently Asked Questions (What Chemicals do you Use to Pressure Wash a House)

What is the best cleaner to pressure wash a house?

The best cleaner to use when pressure washing a house is a mild detergent specifically formulated for pressure washing. These cleaners are designed to effectively remove dirt, grime, and mildew without damaging the surfaces being cleaned.

Look for a cleaner that is environmentally friendly and safe for the type of surface you are washing, such as vinyl siding, stucco, or painted surfaces. It’s important to follow the manufacturer’s instructions and dilution ratios for optimal results and to protect your home.

What chemicals are best to pressure wash siding?

When pressure washing siding, it is generally recommended to use a mixture of water and a mild detergent specifically formulated for pressure washing. These detergents are designed to remove dirt, grime, and stains from various types of siding, including vinyl, aluminum, wood, and stucco.

Avoid using harsh chemicals or bleach unless specifically instructed by the manufacturer for your particular type of siding. Harsh chemicals can damage the siding and surrounding vegetation, and bleach may discolor or deteriorate certain types of siding.

Should I use bleach to pressure wash my house?

It is generally not recommended to use bleach when pressure washing your house unless explicitly instructed by the manufacturer for your particular type of siding. While bleach can effectively kill mold, mildew, and algae, it can also damage certain types of siding and harm surrounding vegetation.

Bleach is a strong chemical that may cause discoloration or deterioration of the siding material, especially on painted surfaces. It is safer to use a mild detergent formulated for pressure washing, which will be effective in cleaning your house without the potential risks associated with bleach.

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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.