The new Colorado River water year began Oct. 1 under a different operating framework, but Arizona’s biggest reductions will not take effect until the start of 2027.
KJZZ reported that the new federal rules begin changing how much water is released from Lake Powell to Lake Mead as the 2027 water year gets underway. Arizona’s own reductions, however, are tied to the calendar year and are expected to begin Jan. 1.
Arizona, California, and Nevada are still working to finalize a Lower Basin agreement that would determine how the reductions are divided among water users. KJZZ reported that Arizona’s top water negotiator, Tom Buschatzke, remains optimistic that the three states can complete the agreement before the end of the year.
Under the current framework, Arizona is expected to reduce its Colorado River use by 760,000 acre-feet in 2027, assuming the Lower Basin states finalize their proposed sharing agreement. ABC15 reported that the reduction would equal about 27% of Arizona’s normal Colorado River allocation.
The exact impact on individual cities and water providers is still being worked out. Phoenix officials told ABC15 that the city does not yet have a final number for how much of the statewide reduction will be reflected in its Central Arizona Project supply.
Arizona Water News reported that the Arizona Water Banking Authority is entering a new phase. Created in 1996, the Water Bank stored unused portions of Arizona’s Colorado River entitlement underground and accumulated long-term storage credits that can be recovered during shortages.
Through 2024, the Water Bank had accumulated more than 4.4 million acre-feet of long-term storage credits, including approximately 3.8 million acre-feet for Arizona uses and more than 600,000 acre-feet on behalf of Nevada.
The Water Bank also has responsibilities for firming certain Central Arizona Project municipal and industrial supplies and for helping meet Arizona’s Tribal firming obligations under the Arizona Water Settlements Act.
As Colorado River shortages deepen, those stored supplies are becoming more important. Instead of focusing primarily on putting additional water underground, the Water Bank is increasingly preparing for the recovery and use of water that has already been stored.
Cronkite News reported that some rural residents around Chino Valley are already dealing with wells that have gone dry, forcing them to rely on water-hauling businesses and private storage tanks.
The Prescott Active Management Area has been considered outside of safe yield for more than two decades, meaning groundwater is being removed faster than it is being replaced. Local officials told Cronkite News that continued growth and groundwater pumping have contributed to declining water levels.
The situation is separate from the Colorado River shortage, but the two issues are connected through Arizona’s broader water supply. As Colorado River deliveries decline, groundwater and stored underground supplies are expected to play a larger role for some communities.
KUNR reported on new research showing that wildfire is burning more land in watersheds that provide water to communities across the West. Researchers analyzed more than 17,000 watersheds and found that the average amount of land burned annually nearly doubled in watersheds serving more than 100,000 people.
Wildfire can temporarily increase runoff, but it can also worsen water quality by sending sediment, nutrients, and debris into rivers, reservoirs, and water treatment systems. Those effects can continue for years after a fire.
Together, the Oct. 1 reports show that the start of the new Colorado River water year is about more than a change on the calendar. Arizona is entering a period when stored water, groundwater, infrastructure, and watershed conditions will become increasingly important as Colorado River supplies decline.
What does this mean for CRIT?
October 1 marks the beginning of a new operating period for the Colorado River, even though Arizona’s larger reductions will not begin until Jan. 1.
CRIT’s senior rights place the Tribe in a different position than many Central Arizona Project users that are expected to experience the largest reductions. Still, changes in releases from Lake Powell to Lake Mead affect the larger river system where CRIT exercises those rights.
The Arizona Water Banking Authority story is also relevant because the agency has responsibilities connected to Tribal water firming. As stored supplies begin to play a larger role during shortages, decisions about how and when that water is recovered will remain part of Arizona’s broader water planning.
The rural groundwater story provides another reminder that legal water rights and physical water availability are not always the same thing. Communities can hold rights or have access to groundwater while still facing declining wells, infrastructure limits, or high costs to move water.
Sources
KJZZ: “New Colorado River rules start Oct. 1, but questions linger about Arizona water cutbacks”
https://www.kjzz.org/politics/2026-10-01/new-colorado-river-rules-start-today-but-questions-linger-about-arizona-water-cutbacks
ABC15 Arizona: “Arizona enters new water year ahead of historic Colorado River cuts”
https://www.abc15.com/news/arizona-enters-new-water-year-ahead-of-historic-colorado-river-cuts
Arizona Water News: “The Arizona Water Banking Authority undergoes a change of direction”
https://www.azwater.gov/news/articles/2026-09-23
Cronkite News: “Heaven sent: Dry wells in rural Arizona force residents to rely on water haulers”
https://cronkitenews.azpbs.org/2026/09/30/rural-arizona-dry-wells-water-haulers/
KUNR Northern Nevada Public Radio: “Western water supplies increasingly threatened by wildfires, new research finds”
https://www.kunr.org/local-stories/2026-10-01/western-water-threatened-wildfires-new-research