Our study investigates why low-income Mexican-American residents living in rural and periurban subdivisions (colonias) in South Texas, one of the poorest regions in the United States, are increasingly dependent upon water vending machines as the main source of drinking water despite continued water infrastructure development. We outline a relational framework that builds on current debates within nature-society scholarship to address this paradox. We demonstrate how institutional enclosure-the creation or repurposing of institutions that curtails public participation in water governance-paired with water quality discourses and daily practices, operate over time to enroll residents as neoliberal subjects. We focus our attention on the emergence of the 'water consumer', or the individual who purchases drinking water from the vending machine. This approach addresses the coproduction of political subjectivities in relation to institutional change and how subjectivity reconstitutes a new hydrosocial relationship mediated by the water vending machine. We argue for a relational approach that attends to the production of political subjectivities as central to, not as a result of, the neoliberalization of nature. © 2014 Pion and its Licensors.