Are you trying to prevent water spots or remove them?

Prevention is simple - don't let water dry on your paint. Keeping a good coat of wax or sealant down will offer protection and make sure that when water does dry its easy to remove the spots.

Removal can be done and may require any number of steps, typically a good claying followed by polish will clear up most average mineral deposits, but in some cases you have to get much more aggressive should the spots have actually etched the clear coat.

All depends on the current state of the paint.

 

Use this stuff, ICE. It works great. After you wash your rig, dry it off really good, apply this. It's super easy to put on, just spray it in an area, wipe it off with a microfiber cloth, and then use a separate DRY microfiber cloth to do a quick buff and WHAMMY! No water spots.

I've used this on my white silvy and my dads black GMC and it works great. It really cools down the surface of the paint, keeps an awesome shine, and smells good too!