I have two 275-gal tanks that are salvaged from local farmers. They originally held nitrogen, so they are safe for plants. I have them connected to a system of rain gutters and stock tank fill valves (think toilet tank float) and my buckets and bags pull water from the gutters as needed. Other than simply checking for malfunctions I don't have to touch it once it is set up. No carrying water or worrying about leaving it.

One thing to always be mindful of is the weight of the water in a full container. My tanks weigh almost as much as a small car when full. Even a 40 gal barrel will weigh over 300 lbs when full. The solid construction of any support structure is imperative to safety.