Program of Training and Social Mobilization for Living with the Semiarid: One Million Rural Cisterns (P1MC), one of the largest programs of rainwater harvesting for human water supply, is underway in Brazil. This article presents an assessment of the P1MC, from the point of view of users. The methodology was based on a survey with 623 interviews in 63 municipalities reached by the programme, in-depth interviews with 32 managers and technicians and 15 users, participant and non-participant observations and image recording. Field works were carried out between February 2009 and July 2011. The results indicate that the presence of rainwater harvesting systems reduced by almost 90% the total time spent in search of water. Results also showed that highly precarious socioeconomic conditions still prevail, which is a limiting factor for the achievement of program effectiveness. The program has achieved its goal of building physical structures, but there are still significant challenges, especially those related to adequate supply of water in quantity and quality. Therefore, public policies for water supply in semiarid rural areas should associate technical issues with management elements considering the social, climatic and economic local conditions.