There is no shelf life for stored water as long as it's free of bacteria. So if you start with a clean jug that is opaque with good water, it can store indefinitely. That assumes it is sealed and cannot get contaminated.
The way I've stored water before is to use is 16 drops of chlorine per gallon of water (something like that undetermined 'capful' per 5 gallons). City water already has chlorine in it, so this is really redundant, but our tap water seems to change composition and so this is so that I know it's state. I fill my container to the rim and put the cap on, spill a little in the process. I use 2 gallon Nalgene jugs, but anything that is not clear will work. I understand that in this state you can leave the water for as long as you want, but the longest I went was about 6 months before I just used it up. You want a very faint bleach smell, like a clean kitchen. If the smell is strong, then you have too much. You are looking for concentrations of about 1 to 5 PPM for drinking water, anything higher is more for sanitation (where you want 50 to 100 PPM).
