This paper explores the work of engineers amidst the fragments of access and use mechanisms that make up water infrastructures in the city of Chennai in south India. It sets its ethnographic investigation against a dual backdrop. One is that infrastructures in the global south have almost unequivocally come to be accepted as fragmented, even as the fragments themselves are little examined. The second is the mandate and will to order that engineering work is presumed to operate on by academic research and city managers alike. This paper brings these two provocations in juxtaposition by examining engineering work that occurs in the fragments of Chennai’s water infrastructures. In doing so, it argues that engineering modern infrastructures involves multiple, often fragmentary epistemologies that rarely fit into a singular overarching tendency, to order or otherwise. It draws attention to the distinct sub-disciplines as well as the layers of technical jobs and technological cultures constituting the profession of engineering. Tracing the social differentiation between some of these engineering pathways, the paper calls for a rethink of what counts as engineering for the purpose of infrastructure research; and how that shapes our visibility and understanding of cities and their socio-technical support structures.