This article examines how sustainability discourse has become a hegemonic framework in contemporary water and energy policies and how, in the process, it reconstitutes the social meaning of water. The argument develops along three lines. First, sustainability often recasts environmental goals through the language of economic growth and technical rationality, shifting decision-making into technocratic arenas where participation and justice are more easily marginalised. Second, institutional and financial instruments such as natural capital accounting, green bonds, and public-private partnerships render water legible as a measurable economic value, narrowing its ethical, cultural, and relational dimensions. Third, drawing on the hydrosocial cycle approach, the article treats water not as a passive resource but as a medium through which social relations and ethical obligations are produced and contested. Bringing these strands together within a critical geographical framework, the study conceptualises the regime of measurability that emerges at the intersection of sustainability discourse and financialisation, while showing its ethical and epistemic consequences through a hydrosocial reading.