Yogyakarta city as the capital of the province of Yogyakarta Special Region has a rapid rate of economic growth. This makes a lot of people are interested to work and earn a living in the city of Yogyakarta. Resulting in a population density increased from time to time. Put pressure so that high demand for housing. However, the amount of land and residential facilities that are available today is no longer possible to meet the high demand for housing in Yogyakarta thoroughly. The rapid urbanization in major cities and metropolitan has caused problems of limitations on the availability of land for housing. To provide livable housing for low income people, the construction of simple flats is one of the solutions in the supply of residential land vertically by utilizing effectively and efficiently. Flats is one of the buildings that can not be separated from the need of water. The need of clean water necessary for flats can be said to be very much. During this time of building flats obtain clean water from taps and groundwater by using wells. With the tremendous need for clean water in an apartment then it will be the more groundwater to be taken by the bunk house. If it is done in the long term will eat bad impact on the environment of Yogyakarta. Of these problems, the conservation of water is one solution that is efficient in meeting the needs of clean water for flats. Conservation of water to be applied is the rainwater harvesting system (Rainwater Harvesting) that can help meet the needs of clean water for building flats. To maximize the performance of the system to harvest rainwater, the flats will be designed to apply the facade design to catch rainwater. 
Keywords: Housing, Rain Water harvesting, Public Space, Yogyakarta.