If you label water bottles with the date, you can drink the newer ones and use the older ones for cooking, hygiene or flushing the loo.
I'd rather risk a bit of plastic getting into my system than face dehydration. We have a lot of water (stored under the kitchen table) but I imagine we'd drink cans of kombucha and other soft drinks and keep the water for other things, if the 'event' happened soon after a Costco visit. If we used the camping stove (which would be in extremis as it's for outdoor use, so in a storm it would be a real 'short straw' activity) I would boil enough water for hot drinks, and store it in thermoses, but otherwise I think we'd get by with cold drinks for a few days.
We're not rural, but I've always had an emergency box, mostly so I know where things are in an emergency. If I had to go rooting through drawers and in random cupboards looking for things (particularly in the dark) I'd never find anything. From memory, there are batteries in there, camping lanterns, thermal hats and gloves, a decent power bank, disposable hand warmers, the obligatory wind-up radio, medication, a first aid kit, toothpaste and hand sanitiser, loo rolls, a notebook and pen, and probably things I've forgotten. We also have a few rechargeable lamps in the house, and I'm going to make a point of charging them all every Sunday so they'll be ready if needed - reminder on my phone. I'm scared of the dark, so knowing there is plenty of light available is important to me. Oh, I've remembered a head torch is in the box, too.
The kitchen is well stocked with food, and always has been. We always have large tubs of lentils, rice, pasta, beans and so on - no good if there is no power and water is limited, but there is also a supply of tins and jars, and pouches with veggie meals such as savoury rice and 3 ban chilli, so we'd be ok for a while without cooking. I've been adding tins of tuna and similar to my weekly shop, so we should manage.
I don't need them now, but if you have women of menstrual age in the house remember to keep san-pro too, and maybe a crossword book, playing cards or children's games depending on who lives with you - there will be no TV in a power cut.
I'm not preparing for the apocalypse (frankly, I'd rather not face that, so would include a cyanide pill if I had one), but am happy to rough it for a few days if the power goes down or the supply chain is disrupted.