Objective: To analyze the challenges for water security in municipalities belonging to the Piracicaba River (SP) sub-basin, during the COVID-19 pandemic. Method: This is an exploratory and bibliographical research with a qualitative approach and case study and with a technical documentary procedure. The data sources were: Water Resources Situation Report; number of COVID-19 cases and deaths obtained from the Brazilian Ministry of Health website. In addition, a questionnaire on aspects related to water was administered to experts from the Technical Chamber for Conservation and Protection of Natural Resources of the Piracicaba, Capivari and Jundiaí River Basin Committees. Results and conclusions: The number of cases and deaths from the COVID-19 pandemic increased significantly in the 1st half of 2021 compared to the same period in 2020. The experts interviewed attributed high importance to prevention measures, the trend of decreasing water availability and the reduction of losses from water distribution systems. Research implications: The research presented theoretical reflections on the COVID-19 pandemic and water security. Water is an extremely important resource, especially in times of epidemics, as occurred with COVID-19. Water security affects the availability of water both to meet the needs of the population and to maintain ecosystems. Originality/value: The research carried out highlights the need for public policies regarding water and sanitation in order to achieve the protection of the population's health and sustainable development.