The idea of the modern city continues to inform urban policies and practices, shaping ideas of what infrastructure is and how it ought to work. While there has long been conflict over its meaning and relevance, particularly in southern cities, alternatives remain difficult to identify. In this paper, we ‘read for difference’ in the policies and practices of sanitation in Kampala, purposefully looking for evidence of an alternative imaginary. We find increasing acceptance of and support for heterogeneous technological artefacts and a shift to consider these as part of wider infrastructures. These sanitation configurations are, at times, no longer framed as temporary placeholders while ‘waiting for modernity’, but instead as pathways towards a not yet predetermined end. What this technological change means for policies, permissions and socio-economic relations is also as yet unclear: the roles and responsibilities of the modern infrastructure ideal have limited significance, but new patterns remain in the making. Further, while we find increased attention to limits and uncertainty, we also see efforts to weave modernist practices (creating legible populations, knowing and controlling nature) into emergent infrastructural configurations. In this context, we consider Kampala not as a complete instantiation of a ‘modest’ approach to infrastructure, but as a place where struggles over infrastructure are rooted in competing, dynamic imaginaries about how the world is and what this means for the cities we build. It is also a place from which we might begin articulating a ‘modest imaginary’ that enables rethinking what infrastructure is and ought to be.