Governments have largely turned to public-private partnerships (PPPs) to manage public services. Although it is difficult to analyze PPPs as discrete and alternative forms of public service organization, they all constitute some forms of partial outsourcing of activities that contribute to the realization of a public service. In water industries, the most common form of PPPs is the concession, in which a private firm finances and operates the public service of water while the infrastructure remains public. This report seeks to answer the question of whether PPPs have contributed successfully to the quality and improvement of water public services all around the world. The paper is organized in three sections. In the first section, the different supposed advantages and costs of PPPs are presented. The second section reviews some of the most important studies on the efficiency of PPPs in water industries. The last section provides some recommendations to improve the use of PPPs in water public services.