The 1906 Convention and the 1944 Treaty establish the distribution of surface water of the Rio Grande (RG), Colorado, and Tijuana Rivers between the United States and Mexico. Neither of these treaties addresses groundwater management. Only Minute 242 to the 1944 Treaty, regulates salinity for groundwater. Specifically, Minute 242.5 establishes that there is a lack of “conclusion by the Governments of the United States and Mexico for a comprehensive agreement on groundwater in the border areas.” The lack of regulation has contributed to overdraft and degradation of the water quality in several aquifers along the US–Mexico border. Recommendations for an institutional and legal framework under an umbrella agreement, addressing water bank as allocation tool, attempt to fill the legal vacuum of international and interstate groundwater management in the US–Mexico border region. In addition, these recommendations can be adapted to other transboundary basins around the world.
