Spring

When water rises to the surface one speaks of a spring or a water source. Springs or sources develop wherever the aquifer surface (water-bearing layer) meets the Earth's surface (layer springs). One speaks of border springs when there is an upwelling of ground or depth water (hypolimnion) due to geological tectonic influences.

Water can also be forced to the surface by ground heat or pressure caused by carbonic acid:

These fault springs form by the water climbing up along the faults in the Earth's crust, rising through fissures and crevices to finally come to the surface.

A spring is only economically exploitable when the water volume delivered is 2000 liters or more. That is why large water resources are tapped through drilling – as is the case with mineral water sources.

The more than 20 sources that supply Gerolsteiner's natural mineral water are named Gerolsteiner, Gerolsteiner Naturell and St. Gero.