A little late to the game, here, but I don't see the big Culligan (or similar) water jugs mentioned. They are around 5 gallons (I think - 18.5 liters), pre-treated, and quite sturdy. You can get hand pumps that go into the bottles, or get a gravity-fed dispenser (no electricity necessary). I don't recommend storing them on their side - about 1 in 20 springs a leak at the mouth - but they don't have a huge footprint, and you can fit a few in the bottom of a closet. If you buy them before hurricane season, they will store fine through the season, and you can drink them and replace / refill them in the off season. We generally keep a few kicking around for power outages in the summer, as we are rural, and when the power goes out, our water pump doesn't work. We use rainwater for flushing and washing, to conserve the treated drinking water.
I have been thinking this over .... given that I am flooded now and will probably be in a draught by August. I already have a reserve tank for generaI use. I am thinking of setting up a reserve tank to water the garden as well as a third tank for a reserve for livestock.
Be the Mr. Rogers of your neighborhood.
A teeny tiny vulgar attempt to get you to buy our stuff