No, Ceramic Pro will not prevent water spotting, but it will allow those pesky water spots to be easily removed without damaging the surface. Because Ceramic Pro creates a protective layer over the substrate, it does not allow the minerals to corrode or etch the surface that Ceramic Pro is protecting, prolonging the life of your metals, paints, gelcoat, plastics, vinyl, etc. Ceramic Pro is a silica-based/glass product and the glass on your windshield can still get water spots, but it is much more resistant to water spots than your clearcoat.