This article critically explores the discourses and practices involved in the definition, promotion, design and use of indicators to manage water resources. It analyzes the manner indicators contribute to shape specific hydrosocial cycles, i.e. specific combinations of water, power and financial flows. The objective pursued is to reveal the politics of water that is made otherwise invisible by the use of indicators. Indeed, while indicators are the product of specific compromises, of particular combinations of negotiated norms and scientifically produced nature, the paper highlights their ability to erase history and naturalize rationales. These issues are investigated through an empirical analysis of a specific indicator, the ‘‘Minimum Flow Requirements’’ (MFR) and its associated biophysical models, developed and used in the South-West of France. The discussion focuses on the underlying assumptions and ensuing framings of the water scarcity problem in the Garonne system over more than two centuries and describes how the system has been lately represented and managed through the use of the MFR. The MFR is shown to be an instrument regulating power and financial relations of heterogeneous actors. It has actively contributed to naturalize water scarcity, despite the contingency of its construction. Finally, it has helped contain the environmental opposition to the management of water in southwestern France.