The 1994 United States-Mexico Treaty for Utilization of Water of the Colorado and Tijuana Rivers and of the Rio Grande alloted to Mexico a guaranteed annual quantity of water from these sources. However the treaty did not provide for the level of quality which became a problem with rapid development in the southern United States in the late 1950's. Mexico protested and entered into negotiations with the United States. In 1974 an international agreement resulted in interpreting the 1944 treaty as guaranteeing Mexico the same quality of water as that being used in the United States.