What If I Pressure Wash a Composite Deck? (Do’s and Don’ts)

Published by: | Updated: February 1, 2023
JCS Refresh Can You Pressure Wash a Composite Deck

Composite decks are low maintenance and look beautiful. However, “low maintenance” does not mean “no maintenance.” 

Every surface still needs proper attention to preserve its look and purpose.  

One way to do this is pressure washing, but how do you clean a composite deck with a pressure washer? Or even a better question, should you? What are the concerns of doing so?

This article will tackle everything, plus more. 

Let’s get started!

Table of Contents - Click to Skip

About The Author

Meet the expert behind this article. 



Co-owner & Service Director

Hey there, I’m Cody. 

A decade of residential and commercial pressure washing led me to start JCS Refresh. Now I can share my knowledge with folks like you. 

Reading from Washington State?

Contact our team for a quote and you might meet me in person.

Quick Answer

Technically, yes, you can pressure wash a composite deck. 

However, improper handling can easily damage it, so, exercise extreme caution or hire a professional.

Can you ruin a deck by pressure washing?

Yes, using high-powered machines always comes with risk. 

Anyone can damage a deck by pressure washing if you don’t consider the correct PSI settings, cleaning agents, and proper handling.

What PSI should I use on a composite deck?

One of the best ways to avoid damage is by setting the proper PSI, which is between 1,500 PSI and 3,100 PSI. Always remember to start on the lower side of the pressure spectrum, working your way up.

What is the best way to clean a composite deck?

Carefully follow the steps below to produce optimal results:

1. Prepare the surface

Remove any items in the surrounding area to ensure they aren’t in your way. Then, cover any fixtures that might be harmed by water damage.

2. Wear the correct attire

Don’t forget to wear the correct attire when using a pressure washer. This includes, but is not limited to; earmuffs, gloves, safety glasses, and enclosed shoes, preferably boots.

3. Spray the surface with a cleaning solution

Start by using a 40-degree nozzle with a solution dispenser to remove any buildup. Then, carefully spray the solution on the surface and scrub each board with a soft bristle brush.

We suggest cleaning in sections, so the cleaning agent doesn’t dry and evaporate before scrubbing. This, can cause the solution to leave behind residue and streaks. 

4. Rinse the deck boards individually 

Always check your deck material guidelines to ensure the correct PSI setting is used, but typically, you can use between 1,500 to 3,100 PSI. 

Also, keep about 8 inches between the nozzle and the deck’s surface to avoid damage.

Can you use Dawn to clean composite decking?

Yes, you can use Dawn to clean your composite deck.

Dawn is a biodegradable, non-toxic dishwashing soap that can effectively remove stains, grease, and oil from most surfaces. 

To do so, dilute ¼ cup of Dawn to a gallon of warm water and use a brush to scrub the surface. If you are dealing with tough oil and grease spots, put a few drops of Dawn directly on the area and clean it with a brush dipped in warm water.

Is OxiClean good for cleaning composite decks?

OxiClean is also safe for composite decks because it produces a chemical reaction that breaks apart buildup from each other.

To do so, start by spreading the OxiClean solution to the designated area with a soft-bristled brush. Then, let it sit for 10 minutes before gently scrubbing and rinsing it off with a hose.


Switching from a wooden to composite deck can be expensive and tedious. Sanding, painting, or staining is no longer necessary, but it doesn’t mean it is also free from dirt and stain.

Fortunately, composite decks can be cleaned easily without hiring a professional. However, if this task is too much of an undertaking, contact a local company and ask about deck cleaning services.

We hope you learned a lot from this guide and have the information needed to set yourself up for success. 

Thank you for reading!