Wyo. Stat. § 41-3-205
The owner of foreign water is hereby declared to have the exclusive right of beneficial use of such foreign water either for immediate application to beneficial use or by impounding the same in a reservoir for future application to beneficial use, as against any claim or right to appropriate any water belonging to the state of Wyoming, and against the right of any Wyoming appropriator to divert water from said interstate stream for beneficial use in Wyoming. All foreign water conveyed or allowed to flow into the state of Wyoming is hereby declared not to be subject to appropriation in Wyoming and not to be subject to diversion under any Wyoming appropriation notwithstanding the same shall flow in the channel of any natural stream within this state and notwithstanding the same may be commingled with the waters in such stream channel owned by the state of Wyoming or by appropriators under the laws of Wyoming.
W.S. 41-3-205