If you store your drinking water before the SHTF, (stuff hits the fan) and you are getting it from existing safe water infrastructure like from the kitchen tap, then probably you are good to go without doing anything. Just use the aforementioned excellent choice USGI or NATO Jerry cans, fill them up, store them someplace cool and dry, (outside rust) and just forget about them for up to several YEARS.
Being kept cool and temperature stable and without sunlight, most if not all of the bad stuff, (if any) will die off over time. It will not multiply. No energy source, (sunlight) nor a food supply. (clean safe water to start with) Water under such conditions does not wear out or become out of date, it will last a very long time. If you think it is necessary, just a couple of drops of bleach per gallon may be added.
Then, to kill the bleach taste years later, if there is any taste of it left, just add a pinch of dry Vitamin C crystals to neutralize the bleach taste. The Vitamin C will also prevent Scurvy, but only if you add at least 25% alcohol to it with is best served in the form of very cheap Rum, which when drunk, will make you groggy. Ignore the last part of this paragraph, it was meant to be only funny. HB of CJ (old coot)
But it is important to use only lined metal cans designed to hold water. If you use cheap thin plastics with the biodegradable starch molecules added, over time the plastic will degrade, dumping bad stuff into the water. Also thin plastic will allow smells to enter the inside of the jug, thus the water. About the only way to easily and safely store drinking water is to use the expensive Jerry Cans designed for it.
