Two main water treatment plants owned by Phnom Penh Water Supply Authority, the biggest water utility company in Cambodia, have been operated since the 1990s. Sub-stations, motors and pump equipment were based on the design of the 1990s, and no post installation changes were made. The facilities have deteriorated and are far less energy efficient than those used currently in Japan. This project under consideration is intended to reduce the GHG emissions by introducing Japanese energy-efficient equipment and the Japanese advanced operation and management.