Urban Metabolism studies, and debate have evolved markedly since the concept was first presented in the 1960s and is now argued by some scholars to be the single most comprehensive metric for urban sustainability. To interrogate the topic, this paper presents an urban metabolism case study for a single metabolic flow within the Greater Accra Metropolitan Area, Ghana; a rapidly growing coastal capital city in Africa. This study explores the relationship between urban metabolism and sustainable urban development by situating water supply analysis within a socio-environmental metabolism study. Using in-depth interviews and secondary data, this study defines the physical flows, cycles, processes and technologies as well as the social, institutional and governance behaviours and structures to construct a single urban socio-environmental metabolic flow. It identifies that even with a focus on a single metabolic flow, a multitude of parallel metabolisms exist spatially and temporally throughout the metropolitan area giving rise to questions of system boundary, urbanisation processes and power structures. This provides for evidence and drives debate for a range of actors to support policy, planning and development decision making towards sustainable urban development. Finally this paper discusses the practicalities for decision making to recommend how urban metabolism studies can be conducted to support positive change towards sustainable urban development. Key words - urban metabolism, hydro-social cycle, water supply, urbanisation, Accra.