Great post Jim. Curb appeal/appearance is one selling point. Liability risks due to slip and fall, followed by lawsuit, is, or should be the obvious reason for gas stations, convenience stores, parking structures, etc.
The EPA issue is the future of pressure washing, from what I am learning. Here in Phoenix the local EPA is focused on air quality, but I foresee that EPA guideline will follow regarding Class 2 waste entering storm drains and/or sanitary sewers.
I am currently looking into expanding my operation to include reclamation. Any suggestions or further information would be greatly appreciated.