Obtaining a Certificate of Occupancy (CO) for real estate projects in Chile is a bureaucratic and confusing process, which often causes delays in the final reception of projects, postponing the occupation by future owners, and impacting the financial flow of developers. This research aims to reduce the duration of the citýs CO process for housing projects in Chile. The research questions are: (1) what are the most relevant inefficiencies in the CO process? (2) What improvement strategies can be used to reduce its duration? (3) Can lean methods be used to reduce this duration? The research method is based on 3 stages: (1) conduct surveys to practitioners involved on the CO process of Chilean housing projects to collect the current inefficiencies and potential improvement strategies, (2) develop a current and future state Value Stream Mapping (VSM) considering the survey information, and (3) implement the future state in a case study through action research. This researchs first contribution to knowledge is a list of inefficiencies and improvement strategies related to the CO in Chilean housing projects. The second contribution is to provide evidence that VSM can be successfully used to reduce the duration of this process in housing projects. The study is limited to housing industry under the Chilean regulatory framework. However, the authors believe that similar results can be obtained in other types of projects dealing with administrative processes such as permitting, and other city and regulatory agency approvals.