The present text follows the doctoral thesis that we defended in the Faculty of Letters of the University of Lisbon, under the theme: "The hydraulic system in the Gothic sacra architecture in Portugal from the 13th to the 16th centuries." This project starts from a concept of architecture understood as a structured set of systems that, in phase, are the concern of the master builder. In this set of systems is included the hydraulic system that we divide into upper hydraulic subsystem and lower hydraulic subsystem, in this specific case we will only refer to the first subsystem evoked. As far as the upper hydraulic subsystem is concerned, we have divided it by solutions found in several buildings belonging to the Portuguese and foreign Gothic and Late Gothic architecture, in order to determine which are the most adopted solutions and the most used aquitectonic elements as auxiliary to the upper hydraulic system.In this article we will focus our attention on the upper hydraulic system present in Lisbon: Santa Maria de Belem Monastery, Ermida de S. Jeronimo, Conceicao a Velha Church and Lisbon Cathedral.
