The Cornell Law School Legal Information Institute states: “Beneficial use is a term most commonly associated with water rights in the western United States and the prior appropriation doctrine. Many state statues describe beneficial use as the basis, measure, and limit of a water right. Because these states define water sources as public resources, non-riparian land owners can acquire a right to the use of a water source when they put its water toward beneficial use. However, the extent of their right is limited by the beneficial use…” Source: beneficial use | Wex | US Law | LII / Legal Information Institute (cornell.edu).