The aim of this workshop is to learn-by-doing the capabilities of Giswater. The workshop will start with an overview of the Giswater project and will continue with the practical use of Giswater 4, the latest release which has been hugely enhanced from back-end to front-end. Not only the performance has been increased, but also new developments have been done. These updates reflect our commitment to open-source solutions more intensely in the scope of water supply and urban drainage.