The water cycle, also known as the hydrologic cycle, describes where water is stored on Earth and how it moves.
Water is stored in the atmosphere, on the land surface, and below the ground. It can be a liquid, a solid, or a gas. Liquid water can be fresh or saline (salty).
Water moves between the places it is stored. It moves at large scales (through watersheds, the atmosphere, and below the Earth's surface) and at very small scales (in people, in plants, and in other organisms).
Water moves both naturally and through the actions of humans. Energy from the sun and the force of gravity drive the continual movement of water on Earth. Human activities impact the water cycle by affecting where water is stored, how it moves, and how clean it is.