The United States and Mexico share responsibility in preserving the quality of their international river system, the Rio Grande / Río Bravo, and several international treaties govern the quantity of water each country must give and take. Because no treaty establishes joint standards for the quality of the river, the North American Agreement on Environmental Cooperation (NAAEC) was created in 1993 as a declaration of principles and objectives concerning the conservation and the protection of the environment as well as a guide of concrete measures to further cooperate on these matters. One particular goal of the NAAEC was to improve water quality in the US-Mexico Border Region, ensuring a clean, safe, and reliable water supply for the area. Although the US and Mexican federal governments have made substantial technical and financial commitments through binational agencies like the North American Development Bank (NADB) and the Border Environment Cooperation Commission (BECC), few empirical studies have assessed the impact of binational expenditures on wastewater infrastructure in this region. This report uses longitudinal panel data regression models to estimate the impact of capital expenditures on water quality made by binational, federal, and state water quality management institutions from 1995 to 2012. This analysis considers expenditures made on both sides of the Rio Grande watershed that constitutes the international border, beginning with El Paso, Texas and ending in the Gulf of Mexico. / text