In many communities, supplying water and sanitation is a huge task, and the fact that these essential services can be carried out by the private sector is a debated issue. This article presents an exploratory study aimed to identify the range of motives for collective action shared by activists of the Italian Movement for ‘Public Water’. In-depth interviews were conducted with 28 activists and were qualitatively analysed. Five main motivational categories emerged: defending the right to water, preserving community ties, opposing to the Government and ‘water sellers’, preserving the environment and money interests. Each motive is based on a specific representation of the issue of water and privatization process. Findings provide further support for the importance of moral convictions and sense of community in collective action development and suggest a critical reconsideration of the role played by collective efficacy. The results are discussed in the framework of the psychosocial literature on collective action and community psychology perspectives on participatory processes. Copyright © 2012 John Wiley & Sons, Ltd.