Pressure washing dos and don’ts

January 23, 2025

Elerein Yanki

Hi, I am Yanki, the founder of bisonclean.com. I have been in the cleaning equipment field for more than 5 years now, and the purpose of this article is to share with you the knowledge related to cleaning equipment from a Chinese supplier's perspective.

Pressure washing cleans and repairs surfaces across domestic, industrial, and commercial applications. It uses high-pressure water spray to quickly impact mold, dirt and dust to achieve a cleaning effect. Whether it is cleaning efficiency or cleanliness, other traditional cleaning methods cannot match. Most pressure washers ship with multiple interchangeable nozzles offering different pressure levels suited to different cleaning applications, giving users flexibility right out of the box.

However, incorrect use can cause surface damage, personal injury, and even environmental harm. Therefore, this article introduces pressure washing dos and don’ts, and provides expert advice and some tips for using pressure washers effectively.

Pressure washing Dos and don’ts

To ensure you use it correctly and safely, here are some things Elerein experts advise you to pay attention to:

1. Proper preparation

Use proper safety equipment

Gloves: protect your hands from detergents and any sharp objects.
Closed-toe shoes: sturdy shoes will not easily slip and get hurt.
Safety glasses: protect your eyes from flying debris, small particles, and water mist.

Read the owner’s manual

Familiarize yourself with the various operations of the pressure washer, including how to start and stop, adjust the pressure level, and switch nozzles. Locate the hoses, connections, and nozzles according to the manual, and make sure there are no signs of wear, leaks, or damage.

Prepare the work area

Remove any breakable items that could create a trip hazard. Or use tarps or plastic sheets to cover plants, windows, electrical outlets, and other items that cannot be moved. If you’re working near siding, inspect it beforehand for loose pieces, cracks, or breaches to prevent water from intruding behind the siding once washing begins.

2. Use the right technique

Choose the right nozzle

Different pressure washer nozzles produce different spray patterns and pressure intensities. A 40-degree nozzle is suited for general washing tasks, such as loosening dirt on redwood or cedar decking and rinsing outdoor furniture, while a 25-degree nozzle tip is better for targeting dirt and grime on concrete and masonry surfaces.

For more information on pressure washer nozzles, please check the “Elerein pressure washer nozzles guide.”

Angle, distance, and method when spraying

Effective angle: The spray wand should be held at a 45-degree angle or steeper (45–60°) to the surface, which prevents forcing dirt deeper into the surface and removes dirt faster.
Optimal distance: A safe spray distance, usually between 6 inches and 2 feet, and adjust as needed. Starting from a farther distance and then moving closer as needed can prevent accidental damage.
Nozzle movement: From top to bottom, from left to right, always use overlapping strokes in a sweeping motion to avoid concentrating pressure in one place, which can cause surface damage.

Spraying techniques for different materials

Wooden surfaces: Use 500-1200 PSI with wide-angle nozzles. The method of cleaning along the direction of the wood grain can reduce the possibility of wood chipping or scratching.
Concrete: 2,500–3,000 PSI with a 0° or 15° nozzle for tough stains.
Brick: 1,000–1,500 PSI with a 25° nozzle — higher pressure erodes mortar joints between bricks.
Siding (vinyl, aluminum, fiber cement): Use medium pressure with a wider nozzle, spraying downward to prevent water from getting behind the siding.

3. Use the proper cleaning solution

Pressure washing with detergents will yield better results, especially for stubborn stains (grease, oil, or mildew). Common detergents on the market include mildew removers, degreasers, and general cleaners. When choosing a detergent, in addition to choosing a matching detergent, you should also pay attention to whether the detergent is biodegradable, which will protect plants, animals, and waterways from chemical damage.

Manufacturing and transportation environments typically require degreasers, while food processing facilities need sanitation-specific detergents meeting safety standards. Food processing, transportation, oil and gas, and waste management sectors face especially strict environmental compliance requirements, so matching the detergent to the setting matters as much as matching it to the surface.

4. Test on a small area

Spot test in an inconspicuous area to ensure the pressure is not too high for that particular material. Testing should begin with the lowest pressure setting on a small area before increasing pressure to avoid surface damage. Adjust settings based on the test results before proceeding.

The taboos of pressure washing

High-pressure water directed at people or animals can cause serious injuries, including cuts, punctures, and impact injuries.
Untrained operators may not have enough knowledge of the functions of the pressure washer, which may lead to errors or accidents such as electrical hazards, kickback,or improper pressure settings.
Don’t use a pressure setting that is too high. High-pressure water can strip paint, making your surfaces look worse than they already are. Aging or weathered wood may be weakened and prone to damage under high pressure. , Forcing water into building materials can lead to mold growth, rot, or interior damage.
Do not use hot water unless this is a hot water pressure washer. Using hot water on a cold water pressure washer may damage the inside of the device and void its warranty.
Using an off-the-shelf chemical not designed for pressure washers can damage seals, pumps, or heating components, so only use detergents formulated for pressure washing equipment.
Do not start working in bad weather. Using an electric pressure washer on rainy and thunderstorm days will increase the risk of electric shock. At the same time, the cleaning agent will also be scattered around under the influence of wind and rain, polluting the environment.
Understand local wastewater treatment and environmental regulations. Some jurisdictions require a permit for high-pressure washing, especially in commercial settings. And some chemicals are prohibited by local regulations.

Conclusion

While pressure washing can achieve very good results when cleaning surfaces, it is also necessary to remember that high pressure water is dangerous. Elerein believes that as long as you follow the contents of this article, choose the right equipment, wear appropriate protective equipment, and follow the operating instructions, you can get the maximum safety protection.

As a professional pressure washer manufacturer in China, Elerein pressure washers all use innovative technology, energy-saving motors, and sturdy pumps, and are committed to providing high-quality pressure washers to dealers. Each Elerein pressure washer undergoes strict quality inspections and fully meets high-intensity commercial and industrial needs. Cooperate with Elerein now to enhance your industry reputation!

FAQs About Pressure Washing Do's and Don'ts

Can I pressure wash my roof?

Yes, you can use high pressure water to wash your roof, but be careful. Elerein recommends that you use low pressure to wash your roof, which will protect the shingles or tiles from being damaged. High-pressure spray can strip the protective granules off shingles, reducing their weather resistance over time, so keeping the pressure low and the nozzle at a safe distance matters more than speed. For more detailed steps, please read “How to pressure wash a roof“.

Is it safe to use a pressure washer to wash your car?

Yes, you can use a water pressure of between approximately 1300 and 1500 PSI and a wide nozzle of 25-40 degrees for washing. This will ensure that you do not damage the paint or sensitive areas. Avoid getting too close to the surface of your car and be careful with areas such as windows and door seals to prevent water from entering.