Using a pressure washer combined with the correct cleaning chemicals to clean your concrete helps remove any tough stains and breakdown all buildups. Grass, leaves, dust, debris, and spills leave marks on your concrete surfaces. Having it cleaned annually will help maintain a clean look year around. Combine that with a housewash to remove mildew and algae can make your home the best looking house in the neighborhood. Not cleaning off all that organic matter on your home can deteriorate the finish on your vinyl siding, hardy board or stucco.