The urban sanctuary of Selinous rose on the Acropolis plateau, over an area rich in fresh water and close to the marshy lagoon of the river Cottone’s estuary. Even if no cult of water and water deities is archaeologically known, the waterscape influenced both the life of the settlement and the sanctuary in several ways. This paper analyses the architectural and spatial development of Selinous’ urban sanctuary, linking the data about its water installations with knowledge on the use of water in Greek rituals and public spaces. The aim is to introduce hypotheses contributing to better understanding the role played by water in Selinous’ urban sanctuary. Moreover, the paper takes into account the iconographies of coinage and literary sources from Selinous to compare them with the data about the settlement’s waterscape. Water installations within the sanctuary of Selinous had no aesthetic value and did not architecturally define religious and social space. Nevertheless, lustral water, with its proper agency, might have acted in social space and during ritual activities important to create a shared sense of community.