1. Precipitation: Rain, snow, sleet, or hail falls to the ground.

2. Infiltration: Some of this precipitation soaks into the ground through the soil and rock layers.

3. Percolation: The infiltrated water continues to move downward, filling spaces between soil particles and rock fractures.

4. Groundwater Zone: This water eventually reaches a zone where the spaces are saturated with water, forming the groundwater zone.

Key Points:

* Not all precipitation becomes groundwater: Some evaporates, runs off into rivers and lakes, or is used by plants.

* The rate of infiltration varies: Factors like soil type, vegetation, and ground slope influence how quickly water seeps into the ground.

* Aquifers: Groundwater is stored in underground layers called aquifers, which act like giant underground reservoirs.

So, in short, the water cycle is the main source of groundwater. Precipitation provides the water that ultimately replenishes the underground aquifers.