Taoyuan City’s hydrological system is composed of reservoirs, rivers, creeks, ponds, and water canals. The regional hydrology also create the unique natural ecology and settlement cultures that inhabit Taoyuan’s tablelands.
Shihmen Reservoir, the third largest reservoir in Taiwan, is located upstream of Dahan River in Taoyuan City. The reservoir currently holds a total of 233 million m3 of water and supplies an average of 800,000 m3 of water per day. The rivers of Taoyuan City are divided into 4 categories according to management authority, namely: rivers administered by the central government, regional drainage systems administered by the central government, rivers administered by the Taoyuan City Government (TYCG), and regional drainage systems administered by the TYCG. Rivers managed by the central government include: Dahan River. Rivers managed by the TYCG include: Nankan River, Jiadong River, Lao-Jie River, Shezi River, Fulin River, Daku River, Guanyin River, and Xinwu River.
Since 1748 CE (Qing Dynasty), many ponds have been built due to the shortage of water resources. The ponds served as water reservoirs for irrigation, and the large number of such ponds gave rise to Taoyuan’s fame as the home to a thousand lakes. To date, most of the water stored within these ponds are used for irrigation. The Construction and Planning Agency of the Ministry of the Interior has selected over 300 ponds as part of the national wetlands in the Taoyuan's Reservoir and Canal Wetland program to conserve the pitang wetland environment.