Who owns the Rio Grande in Texas? The United States and Mexico share the waters of the Rio Grande. The U.S.-Mexico border lies in the middle of the river from El Paso and Juárez to its delta at the Gulf of Mexico east of Brownsville and Matamoros in South Texas. In Mexico, the federal government owns the river water.

Control of the Rio Grande is shared between the United States and Mexico under a complex legal framework managed by the International Boundary and Water Commission (IBWC), or Comisión Internacional de Límites y Aguas (CILA) in Spanish. This binational body was established by the 1944 Water Treaty, which dictates exactly how much water each country is entitled to from the river's main stem and its tributaries. Within the US, the water is further governed by the Rio Grande Compact of 1938, which allocates water between the states of Colorado, New Mexico, and Texas. In 2026, this control is a subject of intense negotiation and friction due to persistent droughts. The IBWC uses a "Minute" system—legal interpretations of the treaty—to adjust water deliveries based on current reservoir levels at the Amistad and Falcon Dams. While the federal governments set the treaties, local control often falls to irrigation districts and city water authorities (like the El Paso Water Utilities), who manage the actual withdrawal of water for farming and municipal use under strict state and federal oversight.