The U.S.-Mexican border not only represents a meeting of two cultures and two countries, but it is also a melting pot mixture where power and responsibilities are shared among local, state and federal agencies from both countries. This meeting of countries and agencies with overlapping power are reasons why change occurs slowly on border water issues. These complexities make the resolution of border water problems more complicated than it would be to resolve the same issues on a river located exclusively within the State of Arizona, or within the Unites States. Some specific border complexities and differences are outlined in this paper.