LAS VEGAS (KTNV) — The state of Nevada has filed a lawsuit against the federal government over the newly issued Colorado River operating guidelines.
The State of Nevada, the Colorado River Commission of Nevada, and the Southern Nevada Water Authority filed the lawsuit Monday morning against the U.S. Department of the Interior and Bureau of Reclamation, challenging new post-2026 operating guidelines for Lake Powell and Lake Mead.
The lawsuit argues the federal government's new rules could cut up to 71% of Nevada's Colorado River water supply, threatening the water security of more than 2.3 million residents in the Las Vegas Valley.
Under the federal government's new Record of Decision and 2027–2028 Operating Guidelines, Nevada could be required to absorb a shortage of 213,556 acre-feet at a 3.6 million acre-foot shortage level — roughly 71% of its entire Colorado River entitlement.
The lawsuit argues this calculation violates federal law and historical practice, which has held Nevada's share of shortages to approximately 4%.
According to the lawsuit, Nevada has reduced Colorado River water consumption by more than 40% since 2002 — from 325,000 acre-feet to 198,570 acre-feet — even as the Las Vegas Valley's population grew by 875,000 people.
Despite this record of conservation, the state says the federal government's new guidelines fail to adequately credit that sacrifice when calculating shortage burdens.
The lawsuit argues the federal government's Final Environmental Impact Statement failed to analyze the economic consequences of water shortages on municipal users — even though the Las Vegas Valley economy is estimated at approximately $180 billion annually. The EIS analyzed economic losses to agriculture and recreation but did not quantify the potential impact on cities like Las Vegas, Henderson, North Las Vegas, and Boulder City, according to the complaint.
The complaint cites the federal government's own admission in the Final EIS that its Draft EIS "was insufficient in the description and interpretation of results" — yet Nevada argues the agency failed to adequately correct those deficiencies in the final document.
The 2027–2028 Operating Guidelines, issued August 21, 2026, take effect October 1, 2026.
