why does 'mineral water' which has trickled through ...............?

Question

mountains and valleys for centuries and eons have a 'use by' or expiry date?

Answer 1

it has been "processed" to be bottled

you can go and drink it for free and maybe get a buggy or larva


but once it gets boiled and processed it costs you $$ and has a use by date also in plastic bottle it starts to get a nasty taste from the plastic

Answer 2

Because over time the water will absorb chemical decomposition from the plastic bottle