If given enough notice to store water and fill 3 good coolers with ice, longer than 2 weeks - we lost power for 2 weeks with a hurricane once and had an electric well pump so no water either. Had set up a system with one cooler allowed to be opened, the others not often. By 2 weeks the water that we’d filled the tub with (for washing not drinking - water with a little bit of bleach) was getting questionable.
Like you, I think the biggest issue would be people.