This paper discusses the ways of articulation between the command and control tools and the economical tools within the scope of the hydro-resource policy implemented by bilateral financial institutions, like the World Bank, at the Salitre and Itapicuru Basins in the Brazilian semi-arid lands. This work also explains the motivations for the choice of the Bahian semi-arid lands for the implementation of a water policy by the World Bank, its intervention strategy for that region and the restructuring ways of the public and private spheres resulting from its implementation. This text discusses the hypothesis that the implemented policy brings the command and control tools under the control of the economical tools, assigning the market the main role in the regulation of water. That new management pattern poses as main challenge the risk of making worse the social-environmental conditions in a region that is characterized by extreme lack of hydro resources, high poverty rates and low capacity for social organization. Besides, the incorporation of users in the management process in a low level context of social organization, particularly of the social segments that defend collective and diffuse interests, may result in the privatization of the public sphere, thus misrepresenting the principles which associate decentralization with democratization.