Because of the urgency of the current water challenges, we need to decide on a water-heritage agenda. In order to do so, we should first disentangle the sometimes confusing relationship between water management and heritage management. Where do water and heritage management meet and how can they serve each other? It is argued that fruitful synergy between the two disciplines can be reached in three dimensions: the historic dimension, the conservation dimension and the planning dimension. The subject of interaction between the two disciplines differs per dimension and relates to the changing water system, the heritage we cherish and a changing living environment respectively. The synergy to be reached between the two disciplines differs accordingly.