The say that spring water is anything that springs from the ground, such as a lake, a river etc. Therefore the water you could be drinking could come from a lake which is often used for other purposes. There is not telling if chemicals are used, however no one can produce product without FDA approval. So I would assume that the water has been purified to ensure that all bacteria, or other harmful agents, have been removed.
Spring water is, by definition, water coming from a spring. I don't quite agree with the idea that it's free of chemicals, though. Chemicals in the land can get in the water. So do the decayed bodies of bugs and leaves.
Bottled spring water, by definition, MUST come from naturally sourced spring water, eg Hepburn.
It would be filtered at factory to ensure its' cleanliness. Spring water has naturally occurring minerals in it, which are good for you. These are collected by the water as it passes through various rock strata underground.
When I was at Zebedee Springs, 'El Questro' Station, WA, was told that water comes underneath the Timor Sea, from South Asian landmass, then 're-appears' in northern WA!