Tile roofs are very popular in the south and west. However, its not the tiles that shed the water. Under the tiles there is a water proof layer that is put down, thats your actual roof. The tiles just look good. Its always a good idea to have your tiles cleaned every 5 years or so to keep the mold off of them as that can penetrate the tile and cause it to erode. And if you want to repair a vent, Critter Quitters are a heck of a lot easier to install than pulling a tile and changing the lead.