What about installing a large plastic tank in-line with your water supply. Say 100 gals or so. This takes out the effort of having to manually rotate your water in containers. Mount it relatively high on concrete blocks so it can gravity feed your water heater. Thus you would have the water STORED in the water heater and the water stored in the tank. An extra spigot at the bottom of the tank would allow for easy drainage into smaller containers. Since the tank would be in-line, the water would never be stale.