This article presents key elements in the evolution of water supply regulation in Colombia over the twentieth century. This is novel in that it contradicts widely accepted and seemingly universal trends in water supply development. By putting apparently recent phenomena into a longer historical trajectory, we are able to nuance the idea of a unidirectional transition from centralized to decentralized governance, as well as the evolution of policies associated with neoliberalization. We find that regulatory development began at the municipal scale in the 1920s, only to be centralized mid-century. By the same token, policies typically associated with neoliberalization – such as corporatization, full cost recovery, and volumetric metering – began in the 1910s and 1920s and not under neoliberalism in the 1980s. The work is based on a database compiled by the authors. The database comprises municipal, departmental and state regulatory interventions from 1909 to 2012.