Until now, research achievements of groundwater such as groundwater to depth distribution, usage, the available amount of development, water quality have been written in the watershed units($25{sim}250km^2$). However, complex topography and geology, and the rivers of our country does not fit. And a clear management standards have not been able to present measures in groundwater quantity, water quality management such as rainfall, groundwater, utilization, water quality, pollution, etc. Therefore, in this study, the classification criterion of subwatershed unit($2.5{sim}25km^2$), which is suitable for topography and geology of Korea, for rainfall-rating, groundwater level-rating, groundwater pollution-rating, groundwater quality-rating presented and proved its efficiency by applying in Hampyeong-Gun area.