Košín Dam is the oldest water reservoir in South Bohemia and it was used as a source of drinkable water for the town. Its dam breaks the Košínský Potok (Košín Stream) and it is 18 m high.

The reservoir is 50 ha large and it contains about 3 million cubic meters of water. The maximal depth is 12.5 m. The water here is suitable for swimming and entry into the water is gradual and shallow. Naturists tend to go to the quiet meadow on the left bank of the pond near a small bay, where access to water is built along natural stairs.