The text analyzes public and private sectors performance in the sanitation policy in the second decade of the 21st century, considering the resumption of discussions about the services privatization. To perform this task, a literature review was conducted to recover the policy trajectory, the analysis of data from the National Sanitation Information System (SNIS) was made to develop the sector's diagnosis, and the study of documents, discourses and strategies of the main social actors was done for an evaluation of the proposals rediscussing the national regulatory framework. In addition to an introduction and concluding observations, the paper was divided into three sections. The first presents a synthesis of the policy trajectory in Brazil. The following introduces a diagnosis of public and private sectors performance in the second decade of the 21st century. And, in the third moment, it recovers the discussion about the increased incidence of private sector from the regulatory transformations experienced. The study concludes that, even after the end of Planasa, centralizing structures were maintained, displacing the protagonism of the Union over the policy towards the states. Alliances between stateists and municipalists were effective in keeping reduced the private initiative participation, on the other hand, also prevented system's decentralization. Given the resurgence of privatization proposals, it is not clear whether the recovery of such alliances will be sufficient to block further attempts to expand private participation. However, it is argued that any substantive change in the current model will depend on a consensus that includes these actors. [ABSTRACT FROM AUTHOR]