It's a lot more expensive than gallon jugs from the grocery store, but this is a GREAT option for 'set it and forget it' prepping. 
 
These portable pouches are the perfect solution for anyone who needs access to clean drinking water in an emergency situation or while on-the-go. Each pouch contains 4.227 fluid ounces of filtered water in an easy-to-carry, Coast Guard approved package that fits right into your survival kit, purse or even your pocket.