The purpose of this thesis is to investigate and find the architectural values, which use for rnoptimization of Public Sanitation Unit (PSU). The PSU project, in this thesis, was designed rnand constructed in Wurerber Kebele, in south-east Ethiopia. The unit has been serving the rncommunity since 2017. The unit has mainly two functions, which are showering and rnlaundry. The general aim of the PSU project was an attempt to construct a water and rnsanitation infrastructure unit, which can be used as a focal point and a catalyst for activating rnrural-urban space. Based on an onsite observation, the constructed shower and laundry rnunit utilization rate, performance, and functionality have low outcomes. This was the core rnproblem of this thesis, which initiates the optimization research on the unit. Therefore, this rnthesis tries to investigate and find the existing situations and the contributing factors for rnthe reduced utilization rate of the PSU. To obtain an optimized architectural PSU design rnmixed descriptive type of research method has used in the research. The first part of the rnresearch is, defining underutilization and factors affecting PSU, evaluating the existing rate rnof utilization of the sanitation unit, and finding the opportunities for improvements. In thernsecond part an observational approach for collecting primary data through onsite field rnobservation, questionnaire survey, and interviews are conducted. Besides, Secondary data rnwere collected from published and unpublished works of literature; meanwhile, the rnresearch tries to claim a valid statement from triangulating these mixed methods. The third rnpart considers case studies from different sanitation practices to explore publicly accepted rnsanitation unit trends. The fourth part has the result and finding from the analysis that rnarticulates the problem, which is related to the topological and geometrical aspects of the rnunit. The functional, technical, behavioral and managerial values are found as the pillars to rnaffect the underutilization of PSU in Wurerber Kebele. Finally, the research finds and rnconcludes an architectural intervention based on the four values is certain to obtain an rnoptimal architectural design. Because underrating these values the PSU could bring adverse rnimpact on the underutilization of the unit. Optimization of these values will increase the rnusage and at the same time the public acceptance of the PSU. rnKeywords: Public sanitation unit (PSU), Optimization, Values, Rate, Underutilization