Water stored in a reservoir built at a certain height above the ground contains [[1]] energy.

Water stored in a reservoir above the ground contains potential energy. Potential energy is the energy possessed by an object by virtue of its position or configuration. Potential energy is a result of work done on an object. For example, while filling up a reservoir above the ground, work is done on water against gravity. This work done on the water is stored in the form of gravitational potential energy. Therefore we can say that water stored in a reservoir contains potential energy.