Groundwater wells typically pump water from which zone?

Groundwater wells typically pump water from the phreatic zone, which is also known as the saturated zone. This zone is characterized by its ability to hold water in the voids between soil particles or rock fractures, which are completely filled with water.

The phreatic zone is located beneath the water table, where pressure is equal to atmospheric pressure, leading to the free movement of water. When a well is drilled into this zone, the water table can be accessed, allowing for efficient extraction of groundwater.

In contrast, the unsaturated zone, situated above the water table, contains both air and water in its pore spaces, but not enough water to be tapped effectively by a well. The capillary zone, which is part of the unsaturated zone, refers specifically to the area where water is held in a thin film around soil particles due to capillary action and is again not suitable for well pumping. Although a confined zone exists that can contain groundwater under pressure, wells typically access the water from the saturated phreatic zone due to practicalities of flow and water availability.