Study on the Bathroom Space and the Application of Same-Floor Drainage in Congregate Housing

There are no regulations in Taiwan that clearly forbid the current practice of configuring a pipeline that passes through the floor of a condo to reach the ceiling of another condo downstairs with different ownership, giving rise to potential disputes during pipeline maintenance. In Japan and China, the regulations for water supply and the drainage system strictly forbid the installation of drainage pipes that pass through the floor of a condo to reach the ceiling of another condo downstairs. In this study, life cycle cost analysis was adopted to investigate the traditional piping system as well as the same-floor drainage system, including the descended floor piping system, the raised floor piping system and a pre-wall piping system. According to the results of the life cycle cost and benefit analysis for pipeline renewal and maintenance, and taking into account the overall pipeline construction cost, although adoption of the same-floor drainage system increases the total cost by about 0.3–2.7%, it shows benefits in terms of pipeline maintenance and construction time. From the perspective of property management, if the same-floor drainage system can be implemented in the initial design stage, operation and management related issues can be minimized to reduce both pipeline maintenance and management costs, achieving the best performance in sustainable construction and maintenance.