The Southern part of The Yogyakarta Special Province and The Central Java Province mostly consist of coastal alluvial plain and beach ridges lying from Parangtritis in the east to Cilacap in the west. Hydrogically the area is characterized by fairly good condition of groundwater. Some part of the area where the studied was conducted is lying between the Serang River and Bogowonto River. The possible groundwater utilization in the future re for the agricultural, domestic and tourism needs. As the area will grow it is neccesary to asses the groundwater condition, because the groundwater is one of the possible water supply sources for the future. The study was conducted to a). identify groundwater condition of the area lying between Serang river and Bogowonto River, including water balance of the area, b). identify possible salt water intrusion into the aquifer of the area especially in the beach ridges close to the sea.