Was asked to include a cost estimate for cleaning parking lots in a bid I'm doing for some convenience stores. They want swept monthly and power washed twice a year. I'm looking at sweepers and the cost isn't too bad, any recommendations though would be great. As far as power washing, I'm looking into the wide deck surface cleaners. Basically 20"+ spinners. What PSI can I hit the asphalt with? How should I handle parking lot lines being removed if its a concern at all. How do I price this kind of service? Should I worry about chemicals for cleaning or just use water.