11 Mistakes Most People Make with a Power Washer

Power-washing is not a mysterious process, but if it’s done improperly, it can do serious damage. On your next power-washing project, be sure to avoid these common mistakes.

By Theresa Clement and Jennifer Noonan | Updated Apr 25, 2022 04:52 PM

Make Pressure Washing a Pressure-Free Chore

pressure washing mistakes

The supreme cleaning power of a pressure washer makes the tool an essential to many homeowners, but, just like all tools with great power, there is great responsibility in how it is used. A pressure washer can speed up a long list of household chores, but if not used correctly, it can cause much damage to siding, windows, cars, plants, and so much more.

Before heading outside to take your new tool for a spin, brush up on the basics of using a pressure washer and read on to know how to avoid the most common mistakes that people make when using it.


1. Using Too Much Pressure

Using a Pressure Washer

If you use too much pressure while power washing, you could punch a hole in vinyl siding, etch concrete, or splinter wood. Avoid damage by starting on the lowest setting, slowly adjusting the pressure on the power washer, and making sure there's sufficient distance between you and the surface you're cleaning.


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2. Using Only Water

Using Cleaners with Pressure Washer

Almost all power-washing jobs require the help of a detergent or chemical cleanser. Begin your exterior cleaning project by spraying the area with an appropriate, environmentally safe detergent that can break up dirt and kill mold. Apply according to the product's instructions, letting it sit if necessary before washing it off.

RELATED: Buyer’s Guide: The Best Pressure Washers


3. Not Protecting Landscaping

Protect Landscaping When Power Washing

Before you start power washing, thoroughly wet down adjacent plantings with a garden hose. This will help ensure that the cleanser you use won't dry on foliage and leave burn marks. If your project takes longer and the plants start to dry off, you may need to water them again. Depending on the chemicals you're using, however, you may instead want to protect the plantings with a tarp.


4. Power-Washing Painted Surfaces

Power-Washing Painted Surfaces

Some painted surfaces might not stand up to even a gentle power washing, especially if they are old or have been exposed to sunlight for long periods. Avoid using a power washer on anything that is painted or stained (that is, if you want it to remain painted or stained), any fiber cement siding, old mortar, and gutters.

RELATED: The Dos and Don’ts of Pressure-Washing


5. Power-Washing Mold-Prone Surfaces

Power-Washing Mold

While a power washer combined with a cleaning solution can be effective at removing mold and mildew, some surfaces like drywall or fabric may not be able to thoroughly dry out before developing mold, and as a result should not be power washed. It’s important that any item or material you power wash is able to dry completely to avoid accidentally causing mold to grow.

RELATED: How to Pressure Wash a Deck for Annual Maintenance


6. Washing in the Wrong Sequence

How to Use Pressure Washer

If you are washing an entire house, start with the roof. (That said, power-washing asphalt shingles with high-pressure jets of water is a bad idea—be sure to research whether it's OK to pressure wash your roof type.) After you've cleaned the roof, work your way down the exterior, then tackle the porch or patio, and finish up with the windows. If you start with the exterior or porch first, the runoff from cleaning the roof may make them filthy again.


7. Using Hot Water

Don't Use Hot Water with Pressure Washer

Commercial power-washing contractors use hot water in industrial applications because it cleans faster. Residential exteriors are not as durable as commercial exteriors, and you could actually warp your vinyl siding or damage other elements like cedar shakes or shingles if you use hot water while power washing.


8. Not Being Familiar with Your Equipment

Types of Pressure Washers

If you don’t know how to use the equipment properly, you can do serious damage while power washing. Make sure you get a thorough demonstration of any rental equipment before leaving with it. And if you have purchased a power washer, read through the instruction manual before using it.

Related: Buyer’s Guide: Pressure Washers


9. Cleaning Windows

pressure washer mistakes cleaning windows

While it’s possible to clean windows with a low-pressure washer, it’s usually not a great idea to use a pressure washer on windows. (For those who have just purchased a new pressure washer, believe us, you should not take your new tool for its first spin on glass!) The power of the washer can break the seals around windows, damage window screens, and shatter glass, especially with a narrow tip at a high-pressure setting. Plus, if any water breaks the seal around the window and seeps into the wall, it could lead to mold and rot indoors.

RELATED: 8 Things You Can Clean With a Pressure Washer


10. Using the Wrong Tip

pressure washing mistakes tip

Most pressure washers come with a handful of different tips. Some provide a wide fan of water, some combine air into the stream, and others focus the water into a narrow stream. For most DIYers, it’s best to start with a wider nozzle at a low power setting, as there is less focused pressure and a lower likelihood of damaging the surface you're cleaning.

RELATED: Electric vs. Gas Pressure Washer: Choosing the Right Cleaning Machine


11. Storing a Pressure Washer with Water in It

pressure washing mistakes storage

Properly storing a pressure washer during colder months of the year can help to extend the tool’s life and keep it running well for the next cleaning job. Always unplug the pressure washer, detach the hose, drain all of the water, drain the detergent tank, and rinse out the nozzles thoroughly. Then, store the pressure washer in a location in which the temperature stays above freezing.


Need a hand with your cleaning project?
Leave the dirty work to the pros. Compare quotes from the best local exterior cleaning experts in your area today.

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