See related link below for a tutorial.
route 18
Surf, cut, fly, strength, waterfall, and dive
all pure water types can learn waterfall ( like panpour and other water types
HM Waterfall can be found at the very end of route 17, the route west of Nuvema and Accumula Towns.
It is at route 18 on an island. use strength if you want to get other items.
HM Waterfall can be found on Route 18 in Pokemon Black and White.
to bad
yes
On route 18
on route 18
route 18
you get it in route 18
Route 18.
Somewhere on route 18
it is at route 18, in corner on farthest island
go to route 18
route 18