What should you not wash with a pressure washer
  • Post category:Pressure Washer
  • Post last modified:November 25, 2022
  • Reading time:5 mins read


Pressure washers are the best way to clean your patio, walkway, and driveway. And they can also be used to blast grime off of wooden decks. But there’s a catch: pressure washers can damage wood if you use them incorrectly. In this guide, we’ll show you what not to wash with a pressure washer so that all your hard work doesn’t go down the drain (pun intended).

Wooden decks

  • Do not use a pressure washer to clean a deck. Pressure washers can strip the paint right off of wooden decks and leave them looking very worn and patchy. If you have an older wooden deck that needs an overall cleaning, you’re better off using a broom or sweeping compound instead.

  • Be careful when using your pressure washer on any wood surfaces. While it’s best to avoid washing your pressure-treated wood with water (which can lead to mold and mildew growth), it is safe to use your pressure washer on cedar, redwood, pine and other softwoods. However, be sure that you don’t let the nozzle get too close as it may cause damage if too much force is applied directly against the surface of these types of woods

Oil/gas stains

It should go without saying that a pressure washer is not designed to remove oil or gas stains. If you want to get rid of these, you’ll need to use a degreaser or chemical solvent first, then clean with the pressure washer.

If your goal is simply to make the stain less visible, try using a pressure washer with a detergent injector or high-pressure nozzle.

Porous masonry

Porous masonry, such as brick and concrete, cannot be pressure washed. With porous masonry, you’ll need to use a scrub brush and warm water while the surface is dry. It’s important to make sure that any dirt or debris has been removed from the surface before you start cleaning it with the pressure washer. You should also have a bucket of clean water nearby so you can rinse away any mud or debris that comes off the porous masonry during scrubbing.

Asphalt shingles

Asphalt shingles are a popular choice of roofing because they’re durable and cost-effective. However, pressure washing can damage asphalt shingles in a number of ways:

  • The granules on the top layer can be damaged and worn down if you use too much pressure on them with your high-powered hose.

  • The sealant between the layers could be damaged by too much pressure, which could lead to water seeping through from above into your home or business below.

  • The rubber underlayment can also get torn by overzealous hosing—this is especially a problem if there are nails between the layers that aren’t properly spaced for maximum resiliency as well as durability.

Aluminum siding

Aluminum siding is not a suitable surface for pressure washing. The high-pressure spray from the pressure washer can cause your aluminum siding to warp or crack. This damage may be hard to see at first, but it will eventually show up as a pitting in your paint job and, most importantly, as an increase in energy costs due to heat loss through those cracks. A simple cleaning with soapy water and a soft cloth will keep your aluminum siding looking great without damaging its finish or causing any damage that could lead to increased utility expenses in the future.

Pets and people

  • Keep people and pets away from the area you are cleaning.

  • You should wear protective clothing, including a hat and goggles.

  • Use a pressure washer with a low pressure setting (less than 1000psi)

Stained concrete

A pressure washer can do more damage than good to stained concrete. If you’ve got a concrete driveway or sidewalk that’s not able to be cleaned using a broom or mop, then you might want to consider calling in a professional. Concrete is porous and can absorb water if it’s too wet. Pressure washing your concrete can cause the pores of the material to open up, which allows water and stains from other sources (like oil) into their structure. This will make your stain worse!

If you’re going for DIY here, try cleaning your sidewalk or driveway with regular old soap before giving it a power wash so that any remaining dirt won’t get pushed down into the pore structure instead of coming off with water alone. You should also avoid using high-pressure settings on harder surfaces like cement because they may crack under pressure!

You need to know the limits of a pressure washer.

You need to know the limits of a pressure washer. Although it can be a powerful cleaning tool, it should not be used to replace other methods of cleaning. A pressure washer is not a substitute for cleaning products or even soap and water. It also shouldn’t be used in place of mops, buckets and scrub brushes if you want to get your surfaces clean.


There are many things you can do with a pressure washer, but it’s important that you know what they are and how to use them properly. If you want to use your power washer for personal or commercial purposes, consider taking a course from an experienced instructor so that you can learn how to operate these machines safely before using them on any surface.