This article contributes to the urban political ecology of water through applied anthropological research methods and praxis. Drawing on two case studies in urban Sonora, Mexico, we contribute to critical studies of infrastructure by focusing on large infrastructural systems and decentralized alternatives to water and sanitation provisioning. We reflect on engaging with residents living on the marginal hillsides of two rapidly urbanizing desert cities using ethnographic methods. In the capital city of Hermosillo, Radonic emphasizes how collaborative reflection with barrio residents led her to reframe her analytical approach to water governance by recognizing informal water infrastructure as a statement of human resilience in the face of social inequality, resource scarcity, and material disrepair. In the border city of Nogales, Kelly-Richards reflects on the outcomes of conducting community-based participatory research with technical students and residents of an informally settled colonia around the construction of a composting toilet, while also investigating municipal government service provision efforts. Our article invites readers to view these infrastructure alternatives as ways to explore how applied anthropology can advance the emancipatory potential of urban political ecology through a collaborative investigation of uneven urbanization and basic service provisioning. We emphasize everyday situated relationships with infrastructure in informally organized neighborhoods. Using praxis to collectively investigate the complex and entangled relations between large piped water and sanitation projects and locally developed alternatives in under serviced areas, the two case studies reveal lessons learned and illuminate grounded research openings for social justice and environmental sustainability. Key words: Applied anthropology, infrastructure, political ecology, praxis, water governance, social justice