HM07 (Waterfall) can be found inside of Cave of Origin.
you look at a waterfall from a cave
HM08 Waterfall is in the Cave of Origin in Sootopolis City.
in the cave of origin
HM7 contains the move Waterfall.
You go around the ocean until you find a waterfall, then you go up the waterfall with HM07.
go to Sootopolis, then go to the cave of origin. You will find a pokeballl in there in which contains the TM Waterfall
go to Stevens haus! near the trees.
look around in mossdeep for Stevens house and it's there
In Soothopolis, inside the Cave of Origin, where you catch Groudon
in the cave in sootoplis city when your going to fight groundon
At Ever Grande City above the waterfall
Learn waterfall and go to EverGrande city