Australian water politics is marked by conceptual and bureaucratic separation of water as discrete matter. The source of this politics of separation is colonial relations with water and the Australian continent. Yet, analysis of the materiality of water illuminates the agency of water as part of an assemblage. This paper seeks to unsettle the treatment of water as separate, discrete matter. It asks how political responses to the public problem of water would change were we to take seriously the vitality of nonhuman bodies. In order to investigate this question, the paper presents an analysis of six objects from the inland deserts of eastern central Australia—two bottles, two bores, and two boats—derived from field and archival research. The analysis draws on recent material approaches and a broadly postcolonial literature to argue that ‘taking seriously’ the matter of water might provide a productive means of reframing the politics of water, by using the concept of the ‘agency of assemblages’ to replace the notion of water as separate. Furthermore, paying greater attention to local Indigenous knowledge provides an alternate epistemology upon which to base decision-making, which both unsettles the separation of water and contributes to an ongoing process of decolonisation.