How do I seal a cracked pipe using epoxy putty?
That stuff is worthless for any water line that is pressurized.  IF the crack does not extend into the tile and wall, one way to patch it would have been a glue-over clamshell repair kit like this:



However, you should try to figure out why the pipe is split. This is unlikely, because you generally only see it in slab floors, but if the wall is concrete and was poured around the pipe, that split could easily be from stress if the pipe wasn't wrapped with foam or rubber.