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, in web and print versions.