In the context of institutional transformations that resulted from the mining expansion in Latin America, this article explores the emergence of a social institutional innovation: community based water monitoring. From a qualitative perspective the emergence of a new community form of environmental control in Argentina and Peru is analyzed. The article contributes to the debate on institutional innovation processes in mining contexts, but focuses on an underexplored aspect, social institutional innovations and their connection with the lack of legitimacy of state environmental institutions. The analysis shows that through a process of re-politicization of pre-existing instruments, community actors design and implement alternative schemes for environmental control.