Hydropower has been foundational to countries’ development plans during the 19th and 20th century and to the industrialised modernity of 21st century. This study applies the sociology of worth (SoW), as detailed by Boltanski and Thévenot (2006), to conceptualise the value assigned to water used for hydropower, since the advent of New Public Management (NPM) reforms, in Italy. The analysis concerns extensive documentary data, from 1992 to 2023, about the Italian case of Santa Giustina Dam, in the Trentino area. It helps to re-construct the calculative narrative of hydropower of the ‘qualified subjects’ who gravitate around the case study. Previous accounting research has demonstrated how accounts play a pivotal role when these subjects face ‘situations’: contingent perturbations of their otherwise perturbation-free field of interactions, such as the advent of reforms. The ‘situations’ force them to explicit and justify their orders of worth. Polarized conflicts among the (now explicit) orders of worth may emerge at this point. This study conceives ‘accounts’ as ways to decode and to find a feasible compromise (rather than a polarizing conflict) among orders of worth of the ‘qualified subjects’, in hydropower. In doing so, it demonstrates how accounts contributed to the spread of the market worth (Chiapello, 2017) at a system level, following NPM reforms, with policy implications and ongoing concerns for social and environmental justice in hydropower.