In this article we build on the concept of incompleteness, as recently developed in both organisational and urban studies, to improve our understanding of the collective actions of grassroots organisations in creating and governing critical infrastructures in the changing and resource-scarce contexts of urban informal settlements. Empirically, the article is informed by the case of resident associations providing critical services and infrastructure in informal settlements in Kisumu, Kenya. Findings suggest three organisational processes that grassroots organisations develop for the production and governance of incomplete grassroots infrastructures: shaping a partial organisation but creating the illusion of a formal and complete organisation; crafting critical (and often hidden) material and organisational infrastructures for the subsistence of dormant (but still visible) structures; and moulding nested infrastructure that shelters layers of floating and autonomous groups embedded in communities. In a resource-poor environment, the strategy is to create incompleteness, less organisation and to keep it partial and limited to a minimum of elements. The article also explores the political implications of organisational and infrastructural incompleteness by examining how it leads to efforts to craft loose and ambiguous governmental arrangements, connecting them materially and politically to formal infrastructure systems. These governmental arrangements are shifting and in the making, and therefore also incomplete. The article reveals how grassroots organisations mobilise a wide range of (in)visibility approaches. It concludes by exposing the hidden power of ‘incompleteness’ and the potential in hiding certain elements of incompleteness from outsiders, while rendering other elements visible when perceived as useful.