Some parts of Australia are dry because rainwater seeps quickly through sandy soils and into the rock below. In parts of Australia this water which seeps through the sandy soil collects underground to form underground lakes. Water from these subterranean lakes can be pumped to the surface and tapped and so used for various purposes above the ground. In fact, extensive underground water resources are available over more than half of Australia's land area, but most of the water is too salty to be used for human consumption or for the irrigation of crops. However, most inland farmers do rely on this water for watering their animals and, where possible, to a lesser extent for irrigation.

Underground water can flow very large distances and can be kept in underground reservoirs for a very long time. Water from these underground reservoirs bubbles to the surface as springs in some parts of the country, and these fare sources of permanent water were vital to early explorers of inland Australia, and to other pioneers last century, who used the springs for survival. But in many places levels have fallen drastically through continuous use over the years. This has necessitated the pumping of the water to the surface. Remarkably, underground water sources in Australia supply about 18% of total water consumption. So you can see it is quite an important source of water in this dry land.