Been storing it for a over a yeah and half now, not to drink but to wash me and cloths or to flush the loo, refreshed most of it few weeks back but missed 3 bottles that were in the kitchen wine rack, noticed yesterday they were missing, the carer has been giving them to my Mum to drink! and Mum is fine so I now know it will last well over a year that lot was 19months old and it hadn't been treated cept by what ever is in it as it comes out of the tap.
I refreashed some barrels 3 years old tap water untreated by myself, and it was fine just give it a shake to put the life back into it.
Don't forget food grade storage.
I get 2litre bottles of water from work. It's tap water from source that they give to people when thier water system Is down because of a burst mains etc for drinking. Like each house gets 6 bottles of 2l per x days or something. That's if they don't get one of those water tanks on wheels inthe community. We test it and the leftovers either get poured away or drank. I just being 2 bottles home every now and again and stick it in the cupboards.