-
Depends on the container
-
You can drink it, just be wary of where you store it.
-
If the water is completely free of bacteria or other living organisms, and if it is in a perfect seal, then yes, it would be drinkable.
-
If water isn't in constant movement, bacteria can grow and multiply in the water, if given the chance. The water then has to be treated. Additionally, depending on where it is stored and at what temperature, it may become toxified with toxins seeping into the water from the container. If it's kept at temperatures well below freezing in a suitable container? It should be fine for a millenia.
-
Yes, if it is stored in a can.
-
It depends. Still water, such as leaving a waterbottle untouched will expire.