HM07 (Waterfall)

Kanto
Four Island in Icefall Cave 1F, east of the southernmost ledge, accessible from the southernmost ladder on B1F. Requires the Volcano Badge to be used out of battle.

Hoenn
Sootopolis City. Gift from Wallace in front of the Gym after calming Groudon and Kyogre (requires Surf). Requires the Rain Badge to be used out of battle.

Sinnoh
Sunyshore City, given by Jasmine at the beach after defeating Volkner. Requires the Beacon Badge to be used out of battle.

Unova
HM05 (Waterfall)