In the high mountain valleys of Kyrgyzstan and Tajikistan, gravity-flow irrigation systems support the production of grains, fodder, vegetables, herbs, and fruits as well as wood for fuel and construction purposes. In the Soviet and post-Soviet periods, major changes in the organization of society and agriculture have occurred which, when combined with the effects of population growth and outmigration in recent decades, have fundamentally altered the normative and organizational arrangements that had sustained hill irrigation in the past. This article presents 2 case studies, one from the Alaikuu area of Tar Valley, Osh Province, Alai mountain range, southern Kyrgyzstan, and the other from the upper Shokhdara Valley in Gorno-Badakhshan, Pamir mountain range, eastern Tajikistan. A combination of rights and obligations form the foundation of self-managed offtake systems, the rules for which reflect existing social relationships. The importance of authority to the effective management of these systems is highlighted. Multiple forms of authority coexist at the local level in the Alai and Pamir ranges because of the recent introduction of formal local government and water governance reforms in both countries and the persistence of informal local political institutions, such as the court of elders in Alaikuu and the village headman in Shokhdara. Population growth and diversified livelihood strategies, especially migration, have encouraged a degree of individualism—an attitude that undermines the recognition of authority required for the collective management of hill irrigation systems. An understanding of the heterogeneous role of authority in irrigation management that does not privilege externally created formal institutions is required for government and nongovernment agencies to support hill irrigation and mountain agriculture.