In order to better align studies of Sri Lankan disaster management with contemporary theorizing and extant research results, this contribution provides a first-of-its-kind comparison of the structure and efficacy of social and organizational network legacies vis-à-vis flood disaster management in both rural and urban areas in Sri Lanka. A mixed methods approach is deployed. Results are based on quantitative analyses of survey data from 52 government and non-government stakeholders, in addition to qualitative input obtained during five focus group interviews and nine unstructured interviews with villagers. Social network analysis (SNA), conducted via UCINET software, examines the degree centrality, closeness centrality, and betweenness centrality of networks in three district secretariat divisions (DSDs), namely Colombo, Elapatha, and Kuruwita, areas that experienced mass flooding events in 2016 and 2017. Results suggest that the rural Kuruwita and Elapatha DSDs demonstrated denser organizational networks respectively compared to the urban Colombo DSD. This in turn led to differentiated perceptions of relief efficacy. In terms of social capital applications for disaster management studies, results suggest that bridging, bonding, and institutional considerations, along with the disaster relief expectations generated as a result, led to the creation of richer interpersonal ties and community-level organizations, particularly pronounced in rural areas, that worked in concert with broader formal networks to better address flood inundations. The study demonstrates that the development and mobilization of various actors and resources through social and organizational networks matter when ameliorating flood disaster impacts, thus imparting lessons for Sri Lanka’s capital region as well as potentially areas in other countries similarly afflicted.