I was looking for a solution to catch rainwater during emergencies, and came across this product:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
It's a 63" wide by 12" high, collapsible swimming pool. It can store and transport easily, and just kept stowed away. I plan on hooking up a hose to the drain plug and gravity feeding it to my water tanks, catching rainwater if needed.
This might be a handy prep with multiple uses. I'll probably leave a review on here once I get it delivered.