Pleasantly demented woman
This is an example. Ever seen the 35-pound plastic jugs-in-boxes that restaurants buy their cooking oil in? - I took one home from the local pub to see if it would make a good water jug. And I think it will. I had to clean it with Dawn to get all the old cooking oil out. The plastic jug itself is not very heavy gauge plastic, so you need to leave it in the box for strength. I took it out, cleaned it, put it back, filled it, stored it. It's a little over 5 gallons in capacity (I forgot to measure as I filled so I went by weight--whole thing, filled, was about 42 pounds).
Plastic is HDPE, code 2.