This analysis presents a historical assessment of water supply and sanitation plans for the municipality of Belém, Brazil. The spirit of the assessment recognizes the importance of studying change in relation to historical dynamics, in addition to critiques of normative rationalism's inability to influence effective change in public policy. The research included interviews with social stakeholders, documentary analysis and direct observation. Three plans elaborated between 1980 and 2015 were studied. The results demonstrate that: (1) the emphasis of normative rationalism contributed to neglecting sanitation services; (2) the principles of intersectorality and social participation are fundamental to evolving from normative rationalism to strategic planning and communication on water supply and sanitation in Belém; (3) a large portion of local stakeholders are contrary to the privatization of sanitation services, while the most technically and economically powerful decision-makers in government defend that the State no longer has sufficient capacity to promote universal service coverage; and (4) a significant portion of civil society in Belém indicated their serious opposition to future scenarios for the water supply and sanitation sector that maintain technocracy in related public policies; however, such perspectives were not considered in the elaboration and implementation processes of government planning.