Arizona joins Nevada in legal challenge against federal water cuts

Arizona’s Department of Water Resources and Governor Katie Hobbs have joined a Nevada lawsuit challenging a federal decision by the Bureau of Reclamation. The legal move follows a federal reduction that slashed Arizona’s share of Colorado River water by nearly a third.

State officials argue that the federal plan forces lower basin states—Arizona, Nevada, and California—to absorb all mandatory reductions. Meanwhile, upper basin states face no mandatory cuts under the plan.

Lower basin cuts and upper basin obligations

Under the federal plan, the lower basin states must collectively cut 3.5 million acre-feet of water over the next two years. Arizona is required to give up 760,000 acre-feet annually for two years. With an additional 300,000 acre-feet in voluntary conservation, the state faces a total loss of more than 1.8 million acre-feet by the end of water year 2028.

An acre-foot equals about 326,000 gallons, which is enough to cover one acre with a foot of water and typically supply three average households for a year. Governor Hobbs and the Arizona Department of Water Resources argue that the Bureau of Reclamation failed to hold upper basin states accountable for their water delivery obligations to lower basin states.

Legal claims and environmental impact statements

Nevada originally filed its lawsuit on August 24, shortly after the Bureau announced a plan to cut Nevada’s annual allocation by 210,000 acre-feet. Nevada’s share provides 90% of the water used in the Las Vegas Valley. Nevada argues that the federal plan violates the Administrative Procedure Act, the National Environmental Policy Act, and the Law of the River.

Arizona’s intervention aims to protect its legal rights while preserving a collaborative path with California and Nevada. State leaders contend that the final environmental impact statement unlawfully fails to require upper basin reservoirs to deliver water to Lake Mead. Lake Mead and Lake Powell currently sit at 27% and 22% capacity, respectively, while upper basin reservoirs remain above 60%.

What this means for families, farmers, and businesses

The water cuts threaten local families, farmers, and businesses that rely on the Colorado River. The Central Arizona Project canal supplies over 30% of Arizona’s water, and future cuts could slash allocations further depending on Lake Powell elevations. The bureau plans to conduct 24-month studies to determine future water releases, with potential reconsultations and steeper cuts as early as June 2027 if releases fall to or below 6 million acre-feet.

Affected residents and businesses should monitor local water policies, follow regional conservation guidelines, and stay informed as the litigation unfolds. Property owners and agricultural operators who depend heavily on local water allocations may wish to consult an attorney to understand how changing federal rules and potential restrictions could impact their specific water rights.

This article is general information based on Courthouse News Service and court or agency records available at publication time. It is not legal advice; laws and deadlines differ by state and by case. Published October 17, 2026.