I add bleach to the cistern periodically. The cistern is for rainwater only, well water does not go in there. The water off metal roof first passes into overflow tubes to catch any roof/gutter debris, the overflow goes to cistern. The water out of the cistern passes through filters (don't know the sizes) and UV light. Once inside, we have further RO filters for drinking water.
The wells are in daily use and are operated by a submersible pump, pressure tank, and pressure pump. My generator can power these. I test my well water at the faucet after the RO system with a TDS meter. I have thought about fitting one of the wells with a hand pump, or at least having one in the shop for emergencies. If shit really hit the fan, I could always pull the submersible pump out of casing and just bring water up with a bucket fashioned from PVC and a rope.
The bidets are powered by the household water pressure. That would be handled by gen at the pressure pump for either the well or rainwater system, depending on whichever I have diverted to the house.
I'm not worried about shelf life. After 5 years I'll just replace the shit.