It's the nature of nature – anything exposed to the elements gets grungier every year. From siding to patios to driveways, decks, and cars. You could scrub these surfaces clean with a brush, chemicals, and a free weekend, or you could pull the trigger on a pressure washer's wand and blast away years of grime in minutes with ordinary water. These pressure washers use a pump to boost your home water pressure to between 1,700 and 3,300 psi. On the low end of that range, you can clean a car; on the high end, you can strip paint off brick or wood, and if you're not careful, skin off bone. We tested four of the most promising units. Over a monthlong period, we used these units to clean siding, wash porches and patio furniture, and strip paint, where applicable. We evaluated them for portability, ease of use, and, of course, end results.