Most of the western states have started general stream adjudication for their important river basins. A water rights priority determines who has the better water right in periods of drought when streamflows are low or when supplies are reduced from failure to maintain infrastructure. Adjudications are necessary to provide legal clarity for all those who have water right claims. When a court of law confirms a water right, that right becomes enforceable against other water users and can be protected from impairment by illegal users.