Existing water utility networks provides a wide, distributed and unexploited hydropower potential. The installation of energy recovery stations on existing infrastructures limits both the required investment and the environmental impact. The counter-rotating runners micro-turbine presented in this paper is a new technology dedicated to the harvesting of energy on drinking water network. An analytical model of the machine’s efficiency – the so-called hill chart – is used to investigate the runners’ speeds command laws that maximize the recovered energy on the wide range of consumer-driven flow discharge experienced on water utilities.