International organizations and their partners often consider water security as a core notion of water governance strategies. Water security is, therefore, mostly addressed as a goal to be achieved. As the definition of a water-secure situation is still under consideration, and considering the lack of distance on the causal relationship between water security and sustainability, this normative perspective seems to be premature. We investigate the reciprocal relationship between water regime integration and water security improvement by focusing on two propositions. Firstly, an integrated water regime spontaneously leads to a water-secure situation. Secondly, water security represents a crucial trigger for water regime evolution by anticipating (a) issues in governance fitting and evolution and (b) new uses rivalries. We conclude that water security could be relevant as a tool for the adaptive management of a water regime.