This paper tries to examine the impact and the origins of the establishment of an artificial water supply network and a sewerage in the urban fabric of Ghent. In what context did they come about, and, if there was, what was their impact on the morphological structure of the city. Did they cause a sweeping change to its genetic code and did they manage to implement a rigorous and rational organization in the fungus of streets, passages, moats and ditches of Ghent. As these networks fulfill a function that was formerly performed by their ‘natural’ counterparts, i.e. rivers, canals and wells, the above-mentioned questions have to be posed in the broader context of the evolution of the urban hydrography of Ghent in general