Water can dissolve the mineral content in the rocks it flows over. Rain and melted snow filter through soil and permeable rock until they are stopped by an impervious rock such as granite.

Water percolates through rock strata, collecting different minerals. Limestone enriches water with calcium; water from the dolomites is rich in magnesium; and volcanic rocks are rich in sodium. Mineral waters emerge as pure springs. These processes create spring water.

History suggests water has been extracted from chalk below th