Volatile Water Farming in Twilight Highlands
The best place for players to farm Volatile Water is from the Muddied Water Elementals in Twilight Highlands. The Muddied Water Elementals can be found between the two towns; Firebeard's Patrol and Dragonmaw Port. People frequent this area at level 84 since both Alliance and Horde have quests for the water elementals. Even though this place can get crowded there are still plenty of water elementals to go around. (Just watch the video below, there are at least 5 people here farming with me).
Volatile Water Farming Video: