This may sound odd, but the easiest way to remove water spots is Turtle Wax Bug and Tar Remover. I have tried all the "products" that "claim" to remove the spots but they don't work so well.
Then I happened to try Turtle Wax Bug and Tar remover on my outboard and it removed the water spots in one pass and left an excellent shine (as it waxes when you buff)
So I tried it on my water stained Jeep, it now looks perfect, no marks at all and this was after trying all the so called spot removers. It also works great on removing brake dust off the rims with no side effects and far easier than the products that are sold to do that.
Don't believe me, try it! You will be convinced
I use it on my boat, 4 jetskis and rims on the cars and they all look like new after an application. Also, on the jetskis, no wax I have ever tried has held up as well.
Far cheaper than the specialty products and puts everything from Meguiers in the trash.
Clay bars work, no doubt but its a lot of work. Turtle wax bug and tar remover is non abrasive (never any paint color on the cloth) and so easy to use. Spray on, wipe then let dry and buff.
Returned 2006 Silver SRT8 (vanished into the unknown!)
2004 Jeep Grand Cherokee Overland
2012 Black Charger SRT8