Tanzania has experienced recurring floods causing injuries, deaths and damage of social service infrastructures. The current study assesses the resilience of water supply physical infrastructure (WSPI) against flood. Questionnaires, interviews and physical observations were conducted to evaluate the problems affecting the WSPI. Most components were found vulnerable to flood impacts. The problems align with the lack of proper maintenance, ageing infrastructures, unplanned settlements, rapid population growth, inefficient communication plans, rapid urbanization and failure of roads infrastructure. Such measures as systematic maintenance coupled with functional critical assets replacement plans, increasing system interconnectedness, ensuring availability of alternative facilities and additional capacities for critical components and clear and functional communication plans with a Public–Private Partnership (PPP) approach will assist in enhancing the system’s capacity to survive disasters. The findings are essential in creating awareness to decision makers on prioritization and budgeting for improving the WSPI resilience to flood.