There is not a lot of difference between mineral and spring water. Mineral water contains dissolved minerals such as salts, sulfur, and gases found naturally from its source. Mineral water is often consumed carbonated. Spring water also comes from a natural source, an underground water source, such as a spring. When a spring water company says it is 100% pure, it is not referring to the purity of the water, but the pure source – 100% from an underground water source. It too has some of the same dissolved minerals of tap water.