Are rinsed out plastic milk jugs safe for storing water?
Cleaned jugs are, but ones that are only rinsed aren't. After the milk is gone, wash the inside of the jug with hot water and anti-bacterial soap. Rinse with super-purified or distilled water to avoid the risk of re-introducing contaminants to the inside of the jug. I store the filled bottles in my cold room for six months, then use the water and replace my stores.