. Palm plantations in Nagan Raya experienced rapid development in terms of expansion in the last five years from 2009 to 2013. In 2009, the total area of palm plantations from 40. 216 hectares to 27. 434 hectares in 2013. Changes in land use should be noted because it can influence mainly on the availability of water in a watershed. One of the processes that affect the outcome of water in a watershed is the interception process. This study was conducted to determine the effect of palm oil interception against the water availibity in the Krueng Isep sub watershed which is a sub-watershed catchment area for planning taps and water sources for DI Jeuram. This research method with direct measurements in the field to get the rainfall, throughfall, and stemflow.The research location is in the palm plantation company PT. Sucfindo located in Kuala Pesisir Subdistrict, Nagan Raya District. The results obtained show that the water availability of the Krueng Isep sub watershed with the condition of land planted with palm wholly unable to supply the water drinking and irrigation demand (total water requirements). However, when sub-watershed with oil palm land conditions is limited still able to supply the total water requirements. The maximum limits allowed or permitted the planting of oil palm in Krueng Isep sub watershed is an area of 95,94 km2.