The Headquarter campus of Istanbul Water and Sewerage Administration (ISKI) includes both administration and operational units (different engineering departments, construction departments, and repair ateliers, etc).  Located on a large piece of land, the formation of the campus has started in an unplanned way, an occasional scattering of buildings depending on that day’s needs. Therefore, some major problems such as lack of spatial organization, inefficient pedestrian and vehicle circulation, lack of open space and recreational opportunities for campus employees exist on the site. There also exist many waste materials of old pipes and other infrastructure materials and machines scattered all around campus.  Moreover, the old and abandoned depo, water purification pools and office buildings constitute a considerable area of the campus. The proposed work is for creating an environmentally friendly and socially comprehensive campus. Thus, the aim of this project is to emphasize the long and impressive past of ISKI through an integrated open space design; to support the productivity of employees through outdoor and built up sports facilities and resting and socializing areas. In the design, utilization of abandoned water treatment facility is proposed for increasing environmental awareness. As a sustainable design approach, the work generates designs for the reuse and recycle of waste materials from ISKI’s operations.