Best Pressure Washing PSI For You | Matching Your PSI to the Task

Pressure washing (AKA power washing) is an effective method for cleaning surfaces. But what exactly is it? What should you use it for? What is the best way to use it effectively? Don’t worry—we’ll be happy to provide the information you need so that you can pressure wash your home safely and efficiently.

What is Pressure Washing?

How Does Pressure Washing Work?

Pressure washing is a cleaning method that uses a high-pressure water spray. You can use it to effectively power wash areas to remove loose paint, mold, grime, dust, mud, and dirt from surfaces and objects. There is a motor, which is either electric or gas-powered, that drives a water pump. The pump will take the water from a source, like a garden hose, and force it through the high-pressure hose. The pump mechanism will compress the water to increase pressure. Once the compressed water is forced through a high-pressure nozzle, the nozzle will restrict the water to continue holding back pressure. The pressure will only be released with a trigger, releasing the water at high-pressure speeds through a spray gun. The pressure can then be adjusted according to the pressure you need.

What Should You Use it For?

Pressure washing is a versatile cleaning method that can be used on many surfaces and objects. But that doesn’t mean it SHOULD. It is important to know which objects are safe to pressure wash and which are not. For example, concrete, any type of vehicle, outdoor furniture, wooden decks, plant pots, garage floors, the exteriors of buildings, agriculture equipment, and driveways would benefit from pressure washing. All of these objects and surfaces are durable and strong. Objects you shouldn’t pressure wash are any living things, electrical panels, air conditioners, painted surfaces, windows, wood siding, certain kinds of outdoor furniture with wood finish or glass, thin fabrics, or lead paint. It may seem obvious that you should avoid pressure washing these items. But, sometimes, if you are not being careful, you can accidentally make contact with those items while pressure washing. For instance, you might be pressure washing the sides of a building and then accidentally directing it into a window. As long as you are careful, you should be able to complete your pressure washing task successfully.

Understanding PSI and GPM for Pressure Washing

Defining PSI and GPM

One thing that will help deepen your understanding of how to use pressure washers is using your knowledge of PSI ( pounds per square inch) and GPM (gallons per minute). The PSI measures the pressure or force of the water from the pressure washer. The higher the PSI, the more effective it is for breaking up tough dirt, stains, and stubborn grime. High PSI is beneficial if surfaces require it, like grimy driveways. Other things like pigeon poop don’t require a higher PSI. Besides PSI, there is also GPM. GPM helps measure the water flow rate of a pressure washer. Essentially, it indicates how much water passes through the machine every minute. It is a critical factor in determining the washer’s cleaning efficiency. The higher the GPM, the more water flows through the machine. This allows for faster cleaning, especially for large surfaces. However, low GPM is great for smaller and more delicate surfaces. So, while PSI determines the force of water, GPM focuses on rinsing away dirt after it has been loosened.

How to Calculate Cleaning Units (CU)

Now that you know what PSI and GPM are, we’ll be able to tell you how PSI and GPM are used to calculate cleaning units. (CU) Cleaning units are what determine the overall cleaning power of a pressure washer. It is calculated by multiplying the PSI by the GPm. For example, a pressure washer with a 3,000 PSI and a 2.0 GPM will have a cleaning power of 6,000 (6000 CU). Knowing this information is very useful so you’ll know beforehand what CU you need for your task, whether spraying off mold or pressure washing your whole driveway.

Balance Power and Safety for Your Pressure Washing Job

Select the Appropriate PSI and Nozzle

With a good grasp of PSI and GPM, you can be provided with more knowledge about PSI to enhance your knowledge. A low PSI is generally between 500-1500 PSI. It is good for surfaces like windows, cars, or softwood. Just be careful that the PSI won’t be too strong to damage anything. A medium PSI (1500-2500 PSI) is suitable for general cleaning tasks like decks, fences, and patios. A high PSI (2500-4000+ PSI) is ideal for heavy-duty areas like concrete cleaning, driveway cleaning, stripping paint, and removing extremely stubborn stains. Another thing you can keep in mind is that your pressure-washing nozzle might have a certain color. These are the spray angles for your pressure washer, which are conveniently color-coded. Red is the lowest spray angle, 0°, while black is the widest, higher than 40°. By determining the best spray angle, you can pressure wash certain spots accurately or cover a large swath of land.

Maintain Proper Distance and Technique

Maintaining the correct distance and using proper techniques when pressure washing is also incredibly important. It will help ensure your safety. A general rule is to start at least 4 ft away from the surface you will pressure wash. Only move closer if needed. The safest distance for a low-pressure wash can be done about 6-12 inches from the surface. Try to hold the wand at a 45° angle for efficient cleaning. Use sweeping motions and overlap each stroke to ensure even cleaning and consistency. Whatever pressure washing job you do, wear eye protection shoes with good traction, and stay away from anything that could be an electrical hazard. Follow this advice to get a safe, successful pressure-washing job finished.