Only saw one person mention it; get lifeboat rations that are in mylar pouches. Good for 5+ years and can handle extreme temps of hot and cold (including freezing/thawing).
Here's a link for them; they're all I trust for extreme temp water storage.
https://www.amazon.com/Datrex-Emergency-Survival-Water-Pouch/dp/B00ANY4EXM/
Use these emergency water pouches. These are used on lifeboats by the Coast Guard.