Hi I would think twice about doing cars in your driveway depending on where you live. I had a problem with neighbors complaining first to me then to the police who told me in a nice way that I live in a residential area and I was not allowed to run any type of business on my driveway. i would definetly go to the custs. house and do it there using the cust. water and electric I have a van set up with water tanks, pressurewasher and a generator and if I go to a cust. house I use my water but thier elect. and no one minds most woul even let me refill my tank if I ask though that has only happened on rare occasions.