Spring Water
A spring is a point where groundwater flows out of the ground, and is thus where the aquifer surface meets the ground surface. Depending on how constant the source of the water is - rainfall or snowmelt that infiltrates the earth - springs can be ephemeral (intermittent), perennial (continuous) or artesian. When they leave the ground they may forms pools or streams.

According to the US Food and Drug Administration, spring water is water that comes out of the ground on its own or is bottled near water that comes out of the ground on its own.

Mineral Springs
Minerals become dissolved in the water as it moves through the underground rocks. This may give the water flavor and even carbon dioxide bubbles, depending upon the nature of the geology through which it passes. This is why spring water is often bottled and sold as mineral water. Springs that contain significant amounts of minerals are sometimes called 'mineral springs'. Springs that contain large amounts of dissolved sodium salts, mostly sodium carbonate, are called 'soda springs'.