3000

3M Scotchgard has a product for water spots but I haven't had a chance to try it yet.

SC30096

I had waterspots from over the weekend, today I used some pure polish and it came right off.. after that you should apply another layer of wax

jdoolitt

I had a water spot problem last week - so bad, that we sent our Lexus back to the dealer to have the spots removed from the finish and windows. They were hard water (calcium) spots from just one evening. I've been detailing cars for about three years, and no amount of vinegar, CLR, or any other stuff I threw on the windows would remove the spot. There were spots all over the finish too - but those were covered under the protection package we purchased (black car, made sense on this one). Anyway - got my Lex back from the dealer two days ago, and while all the spots on the finish have been buffed out, a lot of the spots on the windows remained.

Over half of the spots on the windows were gone, but there were still a ton remaining. I read about Mr. Clean Eraser over on Autopia and gave that a try today. ALL the spots came right off the windows. It took a mild amount of rubbing - but I had tried earlier to scrub the spots off with some pretty agressive stuff (CLR is not to be used around paint), with zero luck. Anyway -- I highly recommend that anyone having issues with water spots on their windows give the Mr. Clean product a shot. I picked up the 4 pack for ~ $4.50 at the grocery store.

tod071

MX-7 is some good stuff, but gets very messy. I've used it and it does remove the water spots, but I have also detailed cars that it didn't remove. I've found these products will remove them better than MX-7.
Water Spot Removers

If anyone uses these, just don't forget to use gloves because they will dry up your hands.