Knowledge of how to articulate the “urban transition” is today urgently needed. Urbanization is on a steadily growing trend that impacts the water cycle as a whole. However, while the effects of urbanised/urbanising areas on water quantity (how much water) have been well studied for flood prevention, other effects –as those related to water quality (which water)– are mostly unknown. Taking hold from the most recent developments on the “water age” concept, i.e. the time that water resides in the landscape before exiting as runoff or evaporation, the project proposes a proof of concept study on the notion of “water-age-neutral” design. This concept envisions the possibility of designing the City-Territory without net impacts on its “natural” water age balance and thus with minimal impacts on water quantity and quality altogether.