A survey was conducted to assess the costs and benefits of the WSPs developed at 197 production units operated by the SUEZ Company and serving a total of 10.6 million consumers in France, Spain, Cuba, Morocco and Macao. The results demonstrate benefits in terms of confidence of clients and health agencies. The main benefits however consist of a better control of hazards, especially new hazards that were previously overlooked, and of the treatments steps which are deemed as the most important for water safety. As the progress achieved is essentially linked with unregulated contaminants, improvements in compliance rate were rarely observed after implementation of WSPs. It is supposed that better control of these hazards, together with improved process control, result in improved safety for the consumers.