The United States and Mexico share the waters of the Colorado River and the Rio Grande. A bilateral water treaty from 1944 (the 1944 Water Treaty) and other binational agreements guide how the two governments share the flows of these rivers.

The ownership and allocation of the water in the Rio Grande is a complex "gold standard" legal framework managed by the International Boundary and Water Commission (IBWC), established by the 1944 Water Treaty between the United States and Mexico. Legally, neither country "owns" the water in its entirety; instead, they are entitled to specific shares based on the river's flow and reservoir levels. In the U.S., the water is further divided among the states of Colorado, New Mexico, and Texas according to the Rio Grande Compact of 1938. Within these states, individual water rights are held by irrigation districts, municipalities, and tribal nations (Pueblos). Because the river is often over-allocated and prone to severe drought, these rights are highly contested and strictly monitored. Mexico is required to deliver a certain amount of water to the U.S. from its tributaries, while the U.S. ensures a flow to Mexico from the Colorado River in a "cross-border" exchange. Ultimately, the water is a public trust managed by government agencies to balance the needs of agriculture, urban drinking water, and the environmental health of the river's fragile ecosystem.