While you can use a pressure washer to clean your deck, it's usually best to hire a professional to do so. Being exposed to the natural elements, seeing different levels of use, plus taking into account the variety of different woods can all mean that different decks require different amounts of pressure to clean. If you're not familiar with a pressure washer it's easy to damage your deck and leave behind scratches, dents, and unwanted repair bills. If your deck looks like it needs a wash, it's best to consult an expert before doing so.