(No water? No electricity) Without water, it's a big problem. I always try to keep a small container of collected water, changing it every couple of days and, of course, using it; I don't like to waste this vital liquid. When there's no electricity, I go to work at my second home.
I have a rainwater barrel and some bottles with water, the water can and two buckets are always filled mainly for the animals and in case of need to flush the toilet, but if it comes to it it won't last long and is never enough. Unless I stop drinking. Laundry and dishes can wait.