Mendoza, the fourth largest City in Argentina, has a double-sided system of drinking-water provision : a centre well connected to a general supply network, and a periphery marked by an archipelago of networks and private initiatives. While the urban public services network has been renationalized, after fifteen yearsofpublic-private-partnership, the desire to universalize the pattern developed under privatization, persists. However, although at the agglomeration scale, there is a will to establish uniform networks and management, at the periphery the technical system is evolving, encouraging the development of micro-networks rather than the expansion of the central one. This article analyses some of outposts and pockets of resistance to the universalization of an urban-model, in two rural districts experiencing urbanization : Los Corralitos and Colonia Molina (Municipality of Guaymallén). It also highlights the role of water quality in the fragmentation of the overall domestic water-supply system.