Water Code § 37856

Lands which were within the Westlands Water District immediately prior to the merger shall, so long as said lands remain in the said district, have a prior right with respect to water to which said district was entitled under any contract with the United States in effect on the date of said merger over (1) lands added to the Westlands Water District as a result of the merger and (2) lands annexed to the said district subsequent to the merger.