Isn't the main issue with storing water that chemicals from the container leak into it over time? Lining it with something like Aluminum foil might help there. Vacuum sealing won't. You have to have a metallic interior if your containers plastic.
i would just buy some of the 1 gallon plastic jugs of distilled or spring water at walmart or some warehouse club...think they are about 60 cents a gallon and should be safe to drink for 3-4 years at least...if you do it yourself you prob have to sterilize jars or this or that and then wonder...
also some of those iodine or chlorine tabs and definitely one of those small hand-operated filter/purifiers(berkey?) might be a better option in terms of portability....
also, i have bought several of these blue 7 gallon poly water jugs at walmart for around $10 each...they are bisphenol-free according to the sticker...very sturdy, too...
I don't see any benefits to vacuum sealing it. If the water doesn't have any bacteria or algae in it, just sealing it is enough. If it does, it will breed even without air. The easiest way is just to find containers to store it in and treat it with chlorine.
Take good water , filter it, then bring to a boil. Don’t use bleach or any other chemicals, just plain ol water. Some people use UV to kill anything else that may be swimming around in there.
Don't use distilled water as this is negatively charged and will draw out any impurities from the container its in. You are sealing with food grade plastic so you should be ok.
Freeze about a quart of water in the bottom of a small bread pan, take the resulting ice cube vacuum seal it. Toss it in your freezer, bacteria will not grow in your frozen water, if you need it, take it out, toss in a cooler and keep away from light.
If it gets to be 20 years, you may want to boil it again if you want to drink it, but so what, you would do the same to any water you found at that point too.
The convenience is that it makes nice cold packs to help keep your cooler cool and its potable water in an easy carry container..