This Recommendation aims to clarify the fundamentals of the water consumption of open and closed-circuit wet cooling towers. It addresses water consumption due to evaporation, water consumption due to blow down, water consumption due to drift loss, and how to minimise the water consumption. A comparison between the results of a well-known water consumption calculation formula and of a proper simulation is also provided. This document was published by the Eurovent Association and was prepared in a joint effort by participants of the Product Group ‘Evaporative Cooling Equipment’ (PG-CT), which represents a vast majority of all manufacturers of these products active on the EMEA market. This Eurovent Recommendation can be downloaded in the English language. If you are interested in the print version of this document, contact the Eurovent Secretariat (firstname.lastname@example.org).