In short, I had to return this dryer because it left spots on the surface of my black car. I tried not to dry it completely so I could wipe the mineral deposit spots off, but it was unavoidable to have some parts of the car dry. The water in the San Diego area is not specially hard. Also, it is a pain dragging the dryer around the garage floor, using an extension cord. It didn't save much time, and I'm much happier back drying my new 2011 Honda Accord with old towels.