Where I live has very hard water. It leaves white residue all over my windows and the paint. Is there anything that can be done to prevent this? Drying isnt really an option as it usually dries before I complete the wash. When I waxed it last time I washed it the spots were gone but I can not feasibly wax it every couple of weeks. Any suggestions would be great. I added a inline RV type filter to filter the water but that didnt help. Thanks for the replies.