No, Ceramic Pro will not prevent water spotting, but it WILL allow those pesky waterspots 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, vinyls 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.