On March 28, 2011, the Colorado Supreme Court dismissed claims from well owners that the State’s decision to curtail their use amounted to an unconstitutional taking. Kobobel v. State, Dept. of Natural Resources, --- P.3d ----, 2011 WL 1106978 (Colo. 2011). The well owners had obtained their decreed water rights before enactment of Colorado’s 1969 Water Right Determination and Administration Act. They first argued their underground water appropriations, having been decreed before the Act when tributary groundwater was not administered by the State, were vested property rights in “unappropriated, nontributary groundwater” and that those rights had been taken by the State without payment of just compensation. They also contended that the State’s cease and desist orders precluding them from using their wells amounted to a regulatory taking because the State only recently issued the orders after decades of allowing the well owners to pump out of priority. Both the U.S. Constitution and the Colorado Constitution prohibit the taking of private property for public use without just compensation. However, the Court rejected the plaintiffs’ arguments that any impermissible taking had occurred. The Court explained that the plaintiffs’ uses, as tributary groundwater, were inherently subject to regulation for the benefit of senior users. Because the well owners were found to have no constitutionally protected property interest in the unfettered use of the water in their wells, the court reasoned, they could not show that the State had taken their property by curtailing the out-of-priority use of their wells.