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Arizona Joins Nevada’s Colorado River Lawsuit Over Cuts

By Drooid · Oct 18, 2026, 2:24 AM UTC · How we work

Summary

Story summary

Arizona Department of Water Resources joined Nevada’s lawsuit on Oct. 16, 2026, setting aside millions for litigation.
Arizona says the plan unfairly cuts Lower Basin states sparing Upper Basin states.
The plan, finalized August 2026, orders water-use cuts for Arizona, California and Nevada starting Jan. 1, 2027.
Arizona’s required cut equals 760,000 acre-feet per year, about 27 % of its allocation.
Arizona Project could lose up to 77 % of its Colorado River water without the agreement.

History

Historical Context

The 1922 Colorado River Compact, signed by the United States and the seven basin states, divided the river’s 15 million acre-feet annual flow between Upper and Lower Basins. In 1968 the Supreme Court upheld the Compact’s allocation, confirming Arizona’s entitlement to roughly 2.8 million acre-feet while limiting Nevada to 300,000 acre-feet. Today Arizona’s 760,000-acre-foot cut under the 2026 Drought Contingency Plan mirrors the Compact’s original dispute, as the state joins Nevada’s lawsuit challenging reduced allocations. If courts follow historic precedent, the litigation could reshape water-sharing rules, forcing the Bureau of Reclamation to renegotiate allocations for all seven basin states.

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Story summary

Arizona Department of Water Resources joined Nevada’s lawsuit on Oct. 16, 2026, setting aside millions for litigation.
Arizona says the plan unfairly cuts Lower Basin states sparing Upper Basin states.
The plan, finalized August 2026, orders water-use cuts for Arizona, California and Nevada starting Jan. 1, 2027.
Arizona’s required cut equals 760,000 acre-feet per year, about 27 % of its allocation.
Arizona Project could lose up to 77 % of its Colorado River water without the agreement.

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