The global function of reservoirs in the modern hydro-climatic system is the conservation of water on the mainland. The multidimensional nature of the reservoir functionality is enormous: guaranteed water supply to industrial enterprises and settlements; hydroelectric (HPP) and pumped storage power plants (PSP); flood control; irrigation of agricultural land; increasing the volume and quality of ecosystem services; use in fishery; water transport development. Meantime, large reservoirs are also characterized by negative environmental effects: land flooding, coastal processing, waterlogging of settlements, salinization, aridification of the landscape of the river floodplain in the downstream, changes in the meteorological regime of the adjacent territory, regional activation of the earth's crust movements. This article analyzes the problems of legal regulation of the processes of the creation and operation of reservoirs. The author investigates the legal status of reservoirs as a human-made water body referring to the legal status of hydraulic structures, entailing the actual formation of reservoirs. The approaches to public administration and the protection of reservoirs used in Russia and other countries are compared. It also provides a brief overview of the legal loopholes in Russia. The purpose of this publication is to identify the shortcomings and contradictions in the legal status of reservoirs in the Russian Federation, which are both a source of drinking water supply, an anthropogenic water body, and water transport. The goal of this study will be achieved by performing the following tasks: The study of foreign and Russian approaches to water management; The analysis of the applicability of the results of the experience of other states to the existing approaches in Russia to determine the legal status of reservoirs and hydraulic structures; Development of proposals for changing the Russian regulatory framework governing the creation and operation of reservoirs and hydraulic structures. The methodological base of the research is constituted by such general scientific methods as dialectical and systemic research methods, analysis, synthesis, induction, deduction, analogy, and alike, and such specific scientific methods as historical and legal research, comparative legal research, formal legal, structural-functional and statistical methods. The study is based on the results of studies conducted by Russian and foreign lawyers, ecologists, hydrologists, as well as economists related to the research topic. The results of the study can be used for effective water management of the creation and operation of reservoirs in the legal aspect for countries with similar problems in the field of water management.