Recently, it has been expected the social infrastructure system must be changed to an environment ally friendly one. Therefore, we proposed a new evaluation method, “ecodesign”, to establish an environment ally friendly system of social infrastructure and performed an evaluation using the proposed method. Four renewal methods for urban water supply systems were evaluated in order to improve the quality and safety of drinking water: Four 1) high-level purified drinking water supply system, 2) domestic water recycling system, 3) movement of treated sewage discharging point to lower reaches, 4) water supply system with PET bottles. We evaluated each water supply system using to ecodesign approach based on citizens' evaluations, the amount of carbon dioxide emission and cost. Accordingly, the domestic water recycling system is the best system from the viewpoint of “ecodesign”. Therefore, we consider that an ecodesign evaluation, with adequate evaluation items provides us important information for planning and implementation of projects to improve social infrastructure.