Previous studies have shown that making informed decisions about water issues requires socio-scientific reasoning (SSR), which is challenging for primary school students. This study focuses on third and fourth graders’ (n=101) perceptions regarding water systems, water sources and usage patterns both at home and within society. The primary school students participated in a water project that lasted for eight lessons. The study was a case study and the data consisted of audio recordings of group conversations on tasks given in the lessons. The students’ perceptions were analyzed using inductive content analysis and structure of observed learning outcome-taxonomy. Students discussed the significance of using water for drinking, food preparation, and maintaining personal hygiene. Students highlighted conservation, health, environmental and household aspects when discussing water conservation and water purification. There is a need to empower primary school students through building scientific literacy and SSR to inform evidence-based decisions related to water issues.