The 'White Vinegar' mentioned above will work. I've used the Chemical Guy's Water Spot Remover with good results on my daughter's car.



The absolute best would be 'wheel cleaning acid' however its harder to find now, and you'll need to wear a mask while using it.

Just be warned, most of the "water spot" removers you'll find at the big-box stores (or autoparts stores) don't work that great.

The longer the water spots sit on the car, the more it will etch into your clear coat. If that happens everything listed above will REDUCE the water spot, but you'll still see them in the paint. you'll need to use a polishing compound to fully remove the spots.