Using a Pressure Washer to Clean a Deck

Written by: Toolsmith Direct

A snap-on pressure washer can leave your deck looking brand new, or seriously damage the wood if you’re not careful. The fact is that the power washer has different settings, and learning to use these settings effectively will help you get the desired results without all the problems.

Pressure Selection

Lower the pressure in the hose as low as you can without losing effectiveness. Test the pressure by blasting a caked on piece of dirt or something to see how the hose is performing. If possible, use snap-on air tools like a fan or rotating tip. When you start the pressure washer, point the tip away from the work area and slowly feather it onto the surface. If you need to test pressure, have a loose board handy so you don’t accidentally etch the wood on your deck.


You need a 40 to 60 degree fan tip to maximize the effectiveness of your efforts. This is the norm for cleaning a wooden deck and will help cut down on unintended etching. It helps to start at a low pressure setting like 600 psi, then crank it up as needed. Absolutely do not use your pressure washer on windows, even if it is hooked up to a small air compressor. Avoid pivoting your arm at the elbow joint, instead move your arm laterally and sweep the deck back and forth to clean it evenly. Another concern is the distance to the wood, where the tip can cause etching at low pressure. Keep the tip a few feet away from the surface of the deck and try to maintain that height throughout the washing.

Start where the deck meets the house, and then sweep outward. Do not go against the grain or you will damage the wood. If you etch the wood, it will need to be replaced.


When you pressure wash a deck, you run the risk of ruining the softer parts of the wood with etching. You may also erode the softer bits with too much direct pressure, which can take seconds if you’re not at a low enough setting. If you want to refinish the deck after washing it, give the surface a thorough sanding. Use nothing higher than 100 grit sandpaper, and avoid fine grains too. You can use an orbital sander, but beware that you are not spot sanding too much.