Tom Bosley -- who famously played Mr. Cunningham on  Happy Days  -- died this morning at a hospital in Rancho Mirage, CA ...
Average estimates: $250 to $420. Power washers can have pressures of 4,000 psi (pounds per square inch) to lesser pressures of maybe a few hundred and run by gas or electric. This means that professionals will probably use one with less pressure to clean a deck and maybe one with higher pressure to clean a patio.
Pressure Washing Costs. 1  Paying a professional to power/pressure wash a basic single level deck with around 250 square feet might cost $150 to $250. Larger decks or those requiring heavy cleaning will cost more; a 20 x 20 foot deck might cost $300 to $400. Expect a minimum charge of at least $100.