These are required by building codes in my area, and I've wondered how effective they really are. It never occurred to me that water would cling to the side of

These are required by building codes in my area, and I've wondered how effective they really are. It never occurred to me that water would cling to the side of the pipe. Some of the other trades suggested that it would make more sense to have them on horizontal runs, but that would probably be less effective.