The model of a variable climate driving natural resource behaviour, use and management of rangelands in Sub-Saharan Africa has been well explored within the non-equilibrium ecology discourse. This paper argues that concepts found in rangelands non-equilibrium thinking have considerable utility if applied to irrigation and river basin management in African savannah landscapes when irrigation has grown in area and coalesced into a larger behavioural unit. The paper suggests that a theory of transition is common to successful rangelands and water management under non-equilibrium conditions. A framework of sustainable water resources utilisation underpinned by non-equilibrium thinking is presented, and some conceptual concerns regarding normative management solutions to water scarcity in Africa are illuminated. Alternative solutions are underpinned by managing water within, and facilitating transitions between, three water supply states: critical water; medial water and bulk water. The discussion is informed by a case study from southwest Tanzania.