I'm starting my owner builder pool and keep getting different answers whether I need tile at the waterline or not. I have an18" raised bond beam on the back that ties into a 18" raised spa. We are using 6" x 24" natural stone veneer panels for the raised parts. I've asked the masonry worker if I could just take the stone all the way to the water line and he said I might get a leak this way because the stone will be permeable. I don't get how this would cause a leak? His plan was to use the stone then do 3" tiles at the waterline. How is that any different? Any body used veneer stone at the waterline? Any problems? Thanks for any advice and answers.