17 Things You Should Never Pressure Wash
When the power of pressure is too mighty
Highlights
Pressure washers are incredibly strong, and can break skin and cause other injuries
A pressure washer should never be used on any living thing—no humans, pets, or plants
Don’t use a pressure washer while working on a ladder or on your roof—the recoil could throw you off balance
Pressure washers and electricity never mix—keep the machine away from breaker boxes
On top of one of the most recognizable basslines in the history of popular music, David Bowie and Queen sang about the kind of intense pressure that “burns a building down, splits a family in two, puts people on the streets.” Thankfully, even the heaviest-duty pressure washers cannot raze whole buildings or destroy lives—but they can break skin, damage paint and siding, and destroy household plants. For that reason, there are parts of your home and items within it that should never be pressure washed. The next time you’re ready to rent or bust out the pressure washer to get your patio, driveway, or stairs shimmering, proceed with caution and make sure to keep those powerful jets away from these 17 things.
17 Things You Should Never Pressure Wash
Pressure washers run on either a gas engine or an electric motor and use a pump and nozzle to bump up the water pressure coming from your hose. A normal garden hose delivers water pressure at a rate of about 50 pounds per square inch, while a pressure washer operates at 1,500 to 4,000 pounds per square inch—they’re very powerful machines. Used on the correct type of surfaces, they can remove stubborn stains and dirt in a heartbeat. But given their tremendous power, there are many items you should absolutely never pressure wash.
1. Asphalt Shingles
High water pressure can strip away the granules on asphalt shingles that protect your roof or knock some of the shingles off altogether—lost shingles can lead to leaks, which can then turn into bigger problems, such as mold. In addition, using a pressure washer while working on a ladder is very dangerous—the recoil from the wand could easily throw you off balance. A proper roof cleaning should always be done by a professional roof cleaning service.
2. Windows
Glass is fragile, and a pressure washer can easily cause your windows to get blown in. Pressure washing your windows could lead to bigger problems than some dirt and grime: you will likely end up replacing your window, and you’ll have a big mess of water and glass to clean up.
3. Air Conditioner Units
Air conditioner units have small, delicate parts, such as fins—using a pressure washer can crush or bend these parts, leading to the unit malfunctioning or shortening its overall lifespan.
4. Electric Meters
Electric meters have cases on them, usually made from glass or plastic. While these cases are meant to protect against extreme weather, they might not be able to withstand the power coming from a pressure washer. Using a pressure washer on an electric meter might cause water to creep into the electrical system.
5. Light Fixtures
Porch lighting or backyard lighting can get dirty over time, especially if you live in a place with harsh weather. Even with all the grime, refrain from cleaning them with a pressure washer as they could become damaged, and you might get water into the electrical elements. To clean your outdoor lights, remove the lightbulbs and clean the unit with a microfiber cloth that has been dampened with soapy water.
6. Gutters
Cleaning clogged gutters is an arduous task, but it’s not one you should expedite with the help of a pressure washer. Pressure washers are so strong that they can pull gutters off of your home or damage them. Clean your gutters by removing any debris by hand and then rinsing them gently with your regular garden hose.
7. Lead Paint
Lead paint is hazardous—it should be carefully removed by a professional. A pressure washer can send bits of lead paint up into the air, giving you no control over where it lands.
8. Mortar or Brick
If your mortar or brick is old, a pressure washer can knock off any loose bits, causing it to wear down sooner than it should, leaving your home vulnerable. In addition, brick is porous and prone to absorbing water. When it absorbs too much, it expands and later contracts as it dries—over time, this causes the brick to weaken, crack, and crumble.
9. Cars
Some pressure washers claim to be suitable for vehicles, and sometimes this is true if the pressure washer is kept on the very lowest setting. But is it worth the risk? Pressure washers have varying power, depending on the angle, the distance the object is from the washer, and the nozzle you use—a small miscalculation could mean a dent in your car or chips in your car’s paint. And don’t think about using a washer under the hood—any water that gets into the engine could lead to expensive repairs.
10. Stained Wood
Unless you intend to remove the stain, never use a pressure washer on stained wood. The power of the washer will pull the stain right off.
11. Pools
In advance of summer bar-be-ques, you might be tempted to clean your pool with a pressure washer—but you should stick to tried-and-true methods like chemicals or robotic pool cleaners. High water pressure, when used on a cement pool, can damage the plastic shell, causing leaks. Vinyl liners are even more susceptible, and the pressure washer can easily tear holes in any place where the liner is brittle.
12. Trees and Shrubs
It might be tempting to give the trees in your yard a good washing, getting rid of any dirt and pollen that’s found their way onto the bark. But the high-pressure water can strip away a tree’s bark, weakening it and leaving it vulnerable to pests and disease. On weaker plants, a pressure washer can damage or kill them by eroding the layer of topsoil and exposing the plant’s roots.
13. Other Living Things
In addition to trees, you should never pressure wash any other living thing—all plants, humans, and pets can be seriously harmed by a pressure washer, causing cuts, bruises, or other abrasions.
14. Wooden Patio Furniture
Patio furniture can take a beating and get dirty quickly while sitting in rain, sun, and other weather extremes. Don’t clean your wooden furniture with a pressure washer, though, as it can cause the wood to split, chip, or splinter. A pressure washer will also remove any wood sealant you have applied to the furniture, which will make it more susceptible to warping, mold, and other issues down the line. To clean wood furniture, look for cleaners that are specially made for wood, and always scrub with the grain pattern.
15. Fiber Cement Siding
Fiber cement siding is becoming increasingly popular due to its noteworthy durability, but it’s not strong enough to withstand the power from a pressure washer, which can damage the siding’s surface. Instead, use a low-pressure hose and bristle brush to clean off any dirt.
16. Generators
Just like with an air conditioning unit, a generator has many small parts and components that can be damaged by a pressure washer. Instead, use a compressor to blow away dust and dirt, then wipe your generator down with a rag and some degreaser.
17. Solar Panels
Using a pressure washer on solar panels can cause the panels to detach from their frame or damage the outer layer of the frame. In fact, some solar panel manufacturers will void your warranty if you pressure wash them.
Things That Can Be Pressure Washed
While we just provided a long list of things that should never be pressure washed, there are several home areas that can benefit from the high power of a pressure washer, including:
Driveways: A pressure washer can make short work of the oil and grease stains living on your driveway
Outdoor stairs: Cement outdoor stairs can be cleaned of their foot traffic with the help of a pressure washer
Garage flooring: If your garage has cement flooring, use a pressure washer to sweep away any debris—just be sure to pick up any objects on the floor first
Non-lead paint: If you’re looking to strip away paint, a pressure washer can do the work in half the time of a scraper
Safety Precautions When Pressure Washing
Pressure washing can make cleaning a breeze, but it’s important to remember that this tool is dangerous and needs to be handled with safety and care. When pressure washing something, be sure to:
Never point a pressure washer at yourself or any other living thing
Wear protective gloves and boots
Plug the pressure washer into a properly grounded receptacle
Test the ground fault circuit interrupter before using the washer
Keep children away from the pressure washer, and never let them use it
Avoid working on ladders or on your roof
Be aware of your surroundings—make sure there is nothing you could trip on while you work
Frequently Asked Questions
Soft washing is an alternative to pressure washing that is more delicate and safe to use on your home’s siding and other delicate areas. Soft washing allows you to effectively clean large areas without the risk of damage using softer pressure and the power of cleaning chemicals.
While some pressure washers, when used at lower settings, are ok to use on tires, we suggest proceeding with caution. While the high pressure alone won’t cause damage to your tires, pressure washers emit high-frequency pulsations that can damage the tires’ sidewall cords. Using a medium-bristle brush and soapy water is a better bet if you want to keep your tires in tip-top shape.
If you’re using water pressure above 2,000 PSI, you should wear a full face shield—at 4,000 PSI, a water jet can easily slice through skin. Always wear heavy-duty, waterproof gloves and rubber boots with metatarsal guards. If you’re working with hot water, make sure your gloves are insulated.