Subzone Cimanuk sub-watershed upstream is playing an important role towards the conservation of water resources for the downstream subzone. To meet the needs of the community, drinking water for agricultural irrigation. However, the amount of land conversion causes the water system in the watershed disturbed. This study aimed to analyze the changes in land use in the watershed Cimanuk upstream and analyze changes in the carrying capacity of the water system upstream use Cimanuk geographic information systems. The analysis shows that it has increased there use of its land area cultivated by horticultural fields such as carrots, potatoes, and other crops. Food and agricultural land development in research, at least from 2005 to 2015, has an adverse impact on the functioning of the Sub-Basin Upstream Cimanuk characterized by decreasing the carrying capacity for water regulation. Or that the development of agricultural land in this area is actually very appropriate if only from the aspect of that is because of relatively fertile landforms (volcanic areas), but the development has destroyed sub-watershed function itself as a water catchment area.