The spell may only be learned from a scroll of Waterga III, which can be purchased from the merchant Susu in Lower Jeuno for 82,250 gil. Scrolls also drop off of Sapphire Quadavs, or Bistre-hearted Malberry and Sozu Bliberry, two Tonberry notorious monsters. In addition, it can also be purchased from the player Auction House under the Black Magic category.
Waterga III is the highest level of the default area-of-effect Black Magic spell dealing Water-based damage. It will damage all creatures within range of a specific target. Waterga III serves as the Black Mage's preferred method of dealing water-elemental area damage until the player can obtain and learn the Waterja spell at level 84.