Navajo Water Rights Overview


Federal reserved Tribal water rights are defined and governed by a body of federal law that recognizes that Tribes have unique property and sovereignty rights over water on their reservations. Because Native Americans have occupied land since time immemorial, Tribes often hold the highest priority water rights. However, Tribal water rights are not determined unless litigation or congressional action has quantified the amount of the right.[1]

The United States Supreme Court has recognized that to achieve the important goal of finality in water adjudications, reserved Tribal water rights must be quantified for historic, present and future uses. Tribal and non-Tribal stakeholders share mutual goals that motivate efforts to resolve conflicts over water.[2] Tribes resolve conflicts through litigation or settlement agreements. Settlements are negotiated by Tribal and non-Tribal parties, approved by congressional action and signed into law by the President of the U.S.

The majority of the Navajo Nation straddles the Upper and Lower Colorado River Basins; therefore, it must abide by a collection of compacts, treaties, statutes, and other authorities referred to as the Law of the Colorado River, which governs water allocations and apportionments.

The process of settling reserved Tribal water rights claims is complex because courts must recognize two set of legal principles: the states’ doctrine of prior appropriation and the federal reserved water rights doctrine.

Key Court Decisions Affecting Water Rights:

Winters v. United States
Most federal reserved Tribal water rights are based on Winters v. United States, 207 U.S. 564 (1908). In the “Winters” decision, the U.S. Supreme Court held that when the reservations were established, sufficient water to fulfill the purposes of the reservations was implicitly reserved. However, while clearly recognizing Tribes’ federally reserved water rights, the Winters decision does not specify either the method for quantifying or any standards for administering these rights. Reserved Tribal water rights are not quantified unless litigation or congressional action has determined the size of the right.[1]
McCarren Amendment 43 u.s.c § 666
In 1952, Congress passed the McCarren Amendment that waived federal sovereign immunity and allowed states to bring the federal government into states’ courts’ general stream adjudications. Later, the U.S. Supreme Court ruled that the amendment also applied to state adjudications of reserved Tribal water rights held in trust by the United States.
Arizona v. California
In 1963, the U.S. Supreme Court ruled that Tribes were entitled to a major share of the Colorado River that would come out of the shares allocable to the states. It reaffirmed Winters doctrine and established the standard of practicably irrigable acreage (PIA) to quantify reserved water rights on a reservation set aside for agricultural purposes. It quantifies the amount of water needed for irrigable land on a reservation.
General Adjudication of All Rights to Use Water in the Gila River System and Source

In 2001, Arizona Supreme Court held that PIA is not the exclusive quantification measure for determining water rights on Tribal lands, and the quantity of water reserved must satisfy both present and future needs of the reservation as a livable homeland.

What is the law of the colorado river?

The Law of the River is a compilation of compacts, acts, guidelines, minutes, and records of decisions.

  • Colorado River Compact
  • Boulder Canyon Act
  • Upper Colorado River Compact
Colorado River Compact: In 1922, the Compact was negotiated by the seven basin states (WY, UT, CO, NM, NV, CA, & AZ) and the federal government. Under the compact, the states established a framework for apportionment of the water supplies between the Upper Basin and the Lower Basin. The dividing line between the two basins is at Lees Ferry, AZ. The Upper Basin and Lower Basin were each apportioned 7.5 million acre-feet (MAF) annually for beneficial consumptive use.


Boulder Canyon Act: In 1928, Congress approved this Act which allocated the Lower Basin States’ water rights. The Act states that a fair division of the first 7.5 MAF of such mainstream waters would give 4.4 MAF annually to California, 2.8 MAF annually to Arizona, and 300,000 AFY to Nevada. However, Congress intended to apportion only the mainstream, leaving to each State their own tributaries. 


Upper Colorado River Compact: In 1948, this Compact was adopted to provide equitable division and apportionment of the Upper Basin. Unlike the Lower Basin, Upper Basin water allocations are based on hydrology and percentages: NM (11.25%), WY (14%), CO (51.75%), and UT (23%). The only state in the Upper Basin with a fixed amount is Arizona (50,000 AFY). Tribal water rights were recognized in the Compact; Article XIX states “(a) Nothing in this compact shall be construed as affecting the obligations of the United States of America to Indian Tribes.”  


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Navajo Water Rights Claims

The Navajo Nation has water rights claims in the Upper and Lower Basins of the Colorado River that are further divided by subbasins and state boundaries. The Nation has settled its claims in the San Juan River Basin Utah and San Juan River Basin New Mexico (authorized by P.L. 87-483 and P.L. 111-11 in New Mexico, and P.L. 116-260 in Utah), both within the Upper Basin. The Nation is currently working to resolve water rights claims in Upper Basin Colorado River Arizona, Lower Basin Colorado River Mainstem, Little Colorado River Basin Arizona, Little Colorado River Basin New Mexico, which includes the Zuni River, and the Rio Grande Basin New Mexico, which includes the Rio Puerco and Rio San Jose.




• Supportive Court Rulings: Winters decision, Arizona v. California, and the Gila River General Stream Adjudication are key court rulings that support Tribal water rights.

• Priority Water Rights: Navajo water rights are often based on the date of the establishment of the reservation land.

• State’s Need for Certainty: State and private parties often desire to have water rights quantified to provide certainty.

• Water Leasing: Navajo’s water rights claims include future needs. If the Nation currently has no use for the water, they may lease this water to non-Tribal users to create income.

• Federal Monies: Federal monies form a substantial part of many settlement packages, often providing for water projects on the reservation.



• Water Competition: The rapid growth of western cities, declining groundwater levels, and increased environmental needs for water all lead to intense competition for limited water supplies and pressure to address Tribal water claims.[2]

• Litigation vs. Settlement: Despite the problems with settlement implementation, such as funding cuts and environmental conflicts, Tribes continue to be interested in negotiating because the courts are much less receptive to Tribal water claims than they were in the past. Today, it is very risky to take a reserved water rights claim to court, either at the state level or to the U.S. Supreme Court. [4]

• Climate Change: Climate variability exacerbates already intense competition for water, adding to the complexity of achieving stable water settlements between Tribes and other water users.[2]

• Cost: The government entities and water users involved in negotiating water rights settlements have all benefited from developments in hydrology, geographic information systems, computer-based modeling, remote sensing, and communications technologies. Generating this information, however, is expensive.[2]


[1] Williams, Susan (1997). Volume 107, Issue 1 (1997) Native Indian Water Rights: Overview of Indian Water Rights

[2] Colby, et. al., 2005. Negotiating Tribal Water Rights-Fulfilling Promises in the Arid West. The University of Arizona Press

[3] Jay F. Stein, Volume 107, Issue 1 (1997) Native Indian Water Rights. The McCarren Amendment and the Administration of Tribal Reserved Water Rights

[4] Bureau of Reclamation, L. C. R. W. T. (n.d.). Law of The River. Law of the River | Lower Colorado Region | Bureau of Reclamation. https://

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