PHOENIX — New federal rules for the Colorado River took effect with the start of the water year on Oct. 1, but Arizona households and farms will not feel changed deliveries from Lake Mead until Jan. 1, 2027, state and federal timelines show.
That split calendar is the core of the story this fall. Reservoir operations between Lake Powell and Lake Mead run on the Oct. 1–Sept. 30 water year, so releases into Mead are already shifting under the Interior Department’s plan. Deliveries out of Mead to the Lower Basin — including the Central Arizona Project that serves the Phoenix metro and large agricultural districts — still follow the Jan. 1–Dec. 31 calendar year.
Arizona, California and Nevada are racing to finish a parallel Lower Basin agreement meant to spread cutbacks that would otherwise fall hardest on Arizona under the federal framework. Tom Buschatzke, director of the Arizona Department of Water Resources and the state’s lead river negotiator, told KJZZ he is “very optimistic” after recent talks and described remaining work as “more dotting I’s and T’s” before boards in the three states review final language.
Talks were complicated when Nevada sued the Interior Department over how the new rules were drafted. John Entsminger, Nevada’s top water official, has separately written that the state remains “committed to working cooperatively towards finalizing and implementing the Lower Basin agreement,” according to reporting on the talks. Buschatzke said negotiators had to work through how the lawsuit fits with the three-state deal but still sees a “positive path forward.”
Even after negotiators sign, Arizona is unique among the seven basin states: the Legislature must approve interstate water-sharing agreements, possibly in a special session. Water has also moved to the center of the 2026 governor’s race between Democratic Gov. Katie Hobbs and Republican challenger Rep. Andy Biggs, raising the political stakes around any vote. Buschatzke has said he believes a finished Lower Basin pact can still clear the Legislature on a bipartisan basis once the text is ready.