Global water resources are subject to increasing supply constraints. We respond by exploring how novel public sector performance reporting can service public accountability. Here our focus is an exploration of the drivers and utility of a unique ‘sustainability’‐focused, publicly disclosed, performance reporting initiative undertaken by a water agency in Australia. Semi‐structured interviews were conducted with a range of individuals from 2013 to 2014. A disclosure index was also constructed to assess the quality of the disclosures. While the key purpose of the reports was to provide managerial accountability with intra‐governmental stakeholders, they were also drawn on to serve a secondary public accountability purpose with external stakeholders. We argue that the prioritisation of internal stakeholders could threaten utility for public accountability purposes. However, in this case, the reports were also found to be largely relevant to the general public. The study demonstrates that reporting developed for managerial accountability purposes can be designed and targeted also to contribute usefully to ancillary public accountability objectives. Our engagement with the public sector to explore the role and effectiveness of novel reporting strategies in support of sustainability and accountability objectives is topical, and contributes to understanding potential solutions in other contexts.