You will find it in icefall cave. You need to have a Pokemon to learn it, then you get to battle one rocket while Lorelei battles another one. If you have questions, email me at bontjes.jeremiah@yahoo.com The HM waterfall is found in icefall cave on four island. On island 4 after defeating the elite 4, you go into the icefall cave. In there you will find somewhat of a puzzle/maze, its pretty easy. After making your way through that you will find a pokeball/ item, it will contain the hm waterfall. In icefall cave. to get waterfall in leaf green ya need to go to icefall cave. i forget exactly were ya get it in icefall cave. but I'm 100% sure that it is in their. catch 60 different types of Pokemon . go to Proffesor Oak and he'll gice you the national pokedex. then go to Bill and he'l give you th Rainbow Ticket which allows you to travel in islands 1-7 . Use the ship in Vermillion City. go into Icefall Cave on island 4. break the ice at the far north end of the room, go up the ladder, then break the ice at the bottom of that section. get off the ice to the bottom, go up the ladder, and there is hm waterfall sitting there. don't say yay