A acquaintance of mine had 3 55-gallon drums in series between the watermain and his house. So when he ran water, it all ran through the drums into his house, maintaining a fresh supply of whatever 3 times 55 gallons is.

The usual issues of contamination arise, but as you note, he didn't worry about his water getting old sitting in a jug in his garage.

I don't know what the water dept. does that keeps water from flowing back into the mains. I assume there's some valve so that if the water in the drums gets contaminated it won't get back into everyone else's water. shrug - Everything's a compromise. We just have to fit them into our style.