Just a thought- we live in the country, and lose power due to thunderstorms/ hurricanes/ice storms. An item that I have used several times for NON-POTABLE water came to my attention today. When not being used, it stores flat against the CEILING in my garage. It is a large kiddie pool, purchased for the grandurchins.
We live in a moderately wet climate- Virginia. We have had a few occasions where we pulled the pool from storage, and slipped it under one of the gutter downspouts. It will snag about 450 gallons of good, clean rainwater. Now, I would not use it for drinking without running it thru a purifier (seen what your gutters look like?
EWWW!) However, you will need water for Mr. Potty. Every gallon in the pool is one I do not have to pump from the well, and a pool full will take care of sanitation water for over a week. The pools are a few bucks at Wally World in the spring/ summer- and with some parachute cord and a couple of screw eyes, store pulled up against the ceiling. And the kids (and child like grandpas) can enjoy them for their original use.