The impact of water management in the urbanisation and urban planning processes. Some preliminary insights from the Roman Eastern Alps. Water management played a crucial role in the urbanisation and urban planning processes in Antiquity, not only because water supply was essential for the economic and social development of each settlement, but also to guarantee the proper management of wastewater. This latter point was extremely significant for those settlements located on a slope or in the foothills, where a proper wastewater management was a key factor in crucial floods from a terrace to the one below it. The paper aims to provide some insights on the relevance of the wastewater handling in the urban development and management of some Roman settlements in the Eastern Alps, between the Regio X – Venetia et Histria and the Province of Noricum.