This is something we've not really done much of in the past. Maybe a couple of small bottles, here and there, but no real emergency-level amounts. We don't have tornados. We don't use a pump on a well. We're not in a rural area.
But we are in an earthquake zone. And I've always had this nagging feeling like I should be more prepared. So this spring, I've begun putting away some emergency water.
Whenever we empty a 2-liter or 64 oz bottle of soda or apple juice, I fill it with filtered water from the fridge. I then label and date the bottle and put it in the garage fridge. Of course, at our family's rate of consuming soda or bottled apple juice, this could take some time. But it's a start.
By dating the bottles, my plan is to pour out old water in 6 months and refill. (The discarded water can water plants or add to the laundry. It won't be wasted.)
I know. It's a plastic bottle not intended for reuse. But this is emergency water we're talking about. Enough water to get through a couple of days, not our usual supply of drinking water.
If a devastating earthquake does happen, at least we've been doing something to prepare for surviving in the aftermath.
edited: here's a site with information on emergency water storage: (link here).
According to this site, I probably should just use the tap water, and not the filtered tap water (our tap water is chlorinated). But, my tap water should keep for one year. There's good info at this site, in regards to how much bleach to add for water storage, whether or not you need to add bleach, and containers.