Ahh, yes. Water has existed since not long after the Big Bang… clean drinkable water that’s not filled with algae and bacteria and been freshly treated to be drinkable without further treatment to avoid causing abdominal distress is a different matter. No matter how carefully it’s been treated and bottled though, some very small (and importantly *safe*) amounts of bacteria remain; given long enough they breed and multiple until eventually they reach unsafe levels. As this happens in a predictable and mathematically consistent way, it can be forecast as to when a sealed bottle of water is unlikely to still be drinkable without further treatment; hence, a date on a bottle of water.
Ahh, yes. Water has existed since not long after the Big Bang… clean drinkable water that’s not filled with algae and bacteria and been freshly treated to be drinkable without further treatment to avoid causing abdominal distress is a different matter. No matter how carefully it’s been treated and bottled though, some very small (and importantly *safe*) amounts of bacteria remain; given long enough they breed and multiple until eventually they reach unsafe levels. As this happens in a predictable and mathematically consistent way, it can be forecast as to when a sealed bottle of water is unlikely to still be drinkable without further treatment; hence, a date on a bottle of water.