The flow of ground water is generally slow and because the water filters through rocks, the main erosional process associated with ground water is solution. Solution is especially common in limestone terranes, as limestone readily undergoes solution in the presence of acidic water, which can come from many sources. The most common source arises from the reaction of rain water with carbon dioxide in the air, forming a solution of dilute carbonic acid. Pollution, especially from sulfur and nitrogen oxides, has increased the acidity of precipitation. Decaying vegetation also releases organic acids such as tannic acid into infiltrating waters. 

In the active zones of flow, acidic ground water dissolves rock to form new cavities and enlarges existing ones, creating networks of underwater caves which can become accessible when the water table subsequently drops. Should the rock layers above these caves become too weak to support themselves, they collapse, breaching the surface and creating sinkholes. Any area characterized by ground water processes and features is referred to as a Karst area. Generally, the formation of underground cavities is relatively constant because it is mostly dependent on the action of infiltrating water. Collapse episodes, however, are most common during periods of rapid water table fluctuation, such as droughts or wet periods. 

There are few depositional features directly associated with ground water. Generally, chemical-rich ground water will flow to the oceans (either directly or by discharging into rivers) or to major ground water basins. There these chemicals may be removed by either precipitation or evaporation, a relatively rare occurrence on continents, although it does occur in caves where it creates cave ornaments such as stalactites (hanging down) and stalagmites (growing upward) and deposits of travertine.