This research investigates medium‐scale disruptive events to understand how these events influence communication and coordination between two interdependent systems (i.e., the water system and the public health system). Medium‐scale events are events that are often overlooked as routine as they occur with more frequency than large‐scale events, yet they have the potential to provide important information about the state and vulnerability of systems, and, if not managed appropriately, can cascade into larger‐scale crises. A survey of US public drinking water systems (N = 471) shows that medium‐scale events promote coordination, especially when those events have a public dimension. Findings also reveal that several features of water systems including surface water sources, system size, and ownership types are associated with higher levels of interaction with the public health systems. Additionally, a network analysis identifies three distinct subnetworks that engage in emergency response activities. The strength of the working relationship was strongly associated with coordinated emergency responses, coordinated public responses, planning, and technical assistance. Findings have implications for both theory and crisis management.