In order to avoid a large-scale disaster in the way western U.S. states manage and allocate water, it will take much more than simply enforcing the century-old allocations set forth in the interstate water compacts. These compacts are legally binding agreements among states that determine how much water from shared rivers is divided. Most of these agreements were established during the early to mid-twentieth century. At that time, each compact was approved by Congress and became legally binding upon all parties. Their purpose was to create a reliable system for allocating water across state lines. Since then, however, many of the original assumptions used to develop these agreements have changed. New and unforeseen challenges facing the state’s ability to allocate their share of water including prolonged droughts, advances in our scientific understanding of how rivers and groundwater interact, and growing populations. Because these changes have increased competition for rapidly diminishing water supplies, many of the original allocation formulas contained within the compacts now serve as sources of friction, causing disputes among neighboring states. The severe conflict illustrated by the 13-year U.S. Supreme Court case Texas v. New Mexico and Colorado, which was finally resolved in May 2026, represents one example of such a dispute. The disagreement exposed what appears to be a basic flaw in the governing structure of water management in the Western United States: rigid administrative systems created for a different hydrologic and demographic reality cannot effectively govern complex, interconnected water systems. As a result, states are often forced to expensive and lengthy litigation to protect their economic and environmental interests. 

One major shortcoming of many twentieth-century compacts lies in the scientific assumptions that existed when they were drafted. When states signed agreements such as the Rio Grande Compact of 1938, water administration had not yet incorporated the modern scientific understanding that groundwater stored underground and water flowing through rivers are often physically connected. As a result, many western states administered surface water flowing through rivers and groundwater stored underground under separate legal and regulatory systems. In the decades since these agreements were signed, state regulators authorized substantial groundwater pumping for agricultural and municipal uses in upstream areas, even as growing scientific evidence demonstrated that intensive groundwater withdrawals could reduce connected river flows. Through this process, separate regulatory systems allowed large amounts of groundwater to be pumped for upstream uses while downstream states argued that those withdrawals depleted water guaranteed to them under the interstate compacts. Rather than reflecting the realities of an interconnected watershed, these separate regulatory systems increasingly placed upstream economic development and downstream compact obligations in tension, reducing deliveries to downstream irrigators and municipalities during periods of water scarcity.

Although administrative failures in responding to changing hydrologic conditions often invite greater federal involvement in resolving interstate conflicts, that involvement typically does not occur until state administrative systems have failed to adapt to changing hydrologic realities. In the Rio Grande litigation, the U.S. Supreme Court reaffirmed that although the United States is not a formal party to the Rio Grande Compact, it has an independent interest in administering the federally operated Rio Grande Project, a system of dams and irrigation infrastructure. As a result, the federal government could not simply be excluded from resolving the dispute. The resulting 2026 settlement includes significant groundwater management and pumping reduction requirements designed to protect the amount of water each state is required to deliver under the compact. These changes may ultimately require some farmers to sell or permanently give up long-held water rights. Although these measures are intended to stabilize the basin, they also demonstrate how delays in reforming administrative systems to incorporate modern hydrologic science into state permitting systems can result in greater judicial oversight of future water management decisions.

Preventing a broad crisis in water management throughout the Western United States will require more than simply enforcing allocation formulas devised nearly a century ago. Achieving long-term economic and environmental sustainability in interstate water policy will depend upon modernizing compact administration to reflect contemporary scientific knowledge. Continued reliance on separate regulatory distinctions developed before the widespread acceptance of modern hydrology is becoming increasingly difficult to justify, both scientifically and legally. Lasting stability will require states to manage rivers and groundwater as parts of the same interconnected system, coordinate their water management practices, and adopt regulatory frameworks that reflect the physical realities of shared river basins rather than outdated assumptions.

Acknowledgement

The Institute for Youth in Policy wishes to acknowledge Irene Kang for editing this policy op-ed.

References

New Mexico Office of the State Engineer & Interstate Stream Commission. (n.d.). Texas v. New Mexico Settlement. https://www.ose.nm.gov/ISC/texas_v_nm_settlement.php

O'Melveny & Myers LLP. (2026, June 5). U.S. Supreme Court approves Rio Grande Compact settlement in Texas v. New Mexico and Colorado, ending a long-running water rights dispute. OMM.com Insights. https://www.omm.com/insights/alerts-publications/us-supreme-court-approves-rio-grande-compact-settlement-in-texas-v-new-mexico-and-colorado-ending-a-long-running-water-rights-dispute/

Texas Commission on Environmental Quality. (2026, June 5). U.S. Supreme Court resolves Rio Grande Compact litigation: Final decree secures Texas water rights. https://www.tceq.texas.gov/news/releases/u-s-supreme-court-resolves-rio-grande-compact-litigation

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https://www.govinfo.gov/content/pkg/STATUTE-53/pdf/STATUTE-53-Pg785.pdf

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