Purpose This paper aims to examine whether the disclosure obligations in areas of water stress required under the revised Global Reporting Initiative standard (GRI) 303 Water and Effluents, 2018 will improve the quality of corporate water reporting. As a key new requirement is to disclose the impact of water withdrawals from (and discharges to) areas experiencing water stress, the authors examine the ambiguity of the term “water stress” and the extent to which following the GRI’s guidance to use the Aqueduct Water Risk Atlas and/or the Water Risk Filter will enable quality corporate water reporting. Design/methodology/approach The study is informed by the notion of public interest reporting, on the basis that the provision of contextual water information is in the public interest. To explore the ambiguity of the term “water stress”, the authors conduct a semi-systematic review of hydrology literature on water stress and water stress indices. To explore the efficacy of using the Aqueduct Water Risk Atlas and/or the Water Risk Filter, the authors review the operation and underlying data sources of both databases. Findings The term “water stress” has a range of definitions and the indicators of water stress encompass a wide variety of differing factors. The Aqueduct Water Risk Atlas and the Water Risk Filter use a combination of different risk indicators and are based on source data of varying quality and granularity. Further, different weightings of water risk information are available to the user, which yield different evaluations of water stress. A variety of approaches are permitted under GRI 303. Practical implications Effective implementation of GRI 303 may be impeded by the ambiguity of the term “water stress”, varying quality and availability of the water stress information and the fact that different water stress calculation options are offered by the water databases. The authors suggest that the GRI closely monitor compliance, implementation approaches and scientific developments in relation to the water stress requirements with a view to providing further guidance and improving future iterations of the standard. Originality/value Whilst there have been many calls for improved contextual water reporting, few previous studies have explored the challenges to implementing reporting requirements related to the determination of “water stress”.