Rainwater harvesting technology is considered an innovative and effective mechanism for reducing drinking water risks due to arsenic contamination and water salinity in coastal Bangladesh. However, adoption of such tanks remains elusive. Most studies on disaster risk communication are predominantly based on individual-level cognitive modeling approaches, which fail to address the role of social groups, human relations, and other collective social factors in the dissemination process of disaster preventive measures. From the viewpoint of social implementation, community adoption of unfamiliar technology for disaster risk mitigation and preparedness requires another approach. Given the challenge to promote rainwater harvesting technology in the study area of coastal Bangladesh, this study examines the role of various social networks including cohesive groups (friends), structural equivalent groups (individuals who have the same position in society), and spatial groups (neighbors) in three information sharing and processing activities-hearing, observation, and discussion. Results show that those individuals who have similar cohesive affiliations tend to become hearing and discussion partners. Cohesive groups share a learning opportunity and are bounded by normative constraints in terms of direct and intimate social relations. Spatial groups facilitate observation, which provides visual learning. Structurally equivalent groups are not relevant in adoption dissemination; therefore competition or similar social environment did not influence the rainwater tank dissemination activities.