Take the canteen to Dangruf Wadi and head north. You will go through two geysers that move you up to a higher ledge. The first geyser is at I-8, and the next is at the far northeast area of the zone, at J-3. After going up that geyser you will follow an unmarked path leading northeast into a hidden section of North Gustaberg.
Once in North Gustaberg head east, cross the bridge, then go further east to the waterfall.