A survey of the literature revealed that it is difficult, indeed virtually impossible, to get meaningful information about the likely performance of dewatering equipment. As a consequence customers have sometimes specified impossible target performances and suppliers have unwisely agreed to them. Dewatering has major consequences for downstream processes, for example sizing dryers correctly is directly dependent upon the amount of water that has to be evaporated, i.e. the dry solids content of the cake. This paper will present the results of a survey of operational sludge dewatering, including the type of equipment, conditioner and type of sludge undertaken with the cooperation of members of Water UK. The results should assist designers and specifiers of sludge treatment processes and enable operators to benchmark the performance of their own equipment.