We use these water bags:     (You need to Login or Register

Quick filling, large capacity, easy to clean, will not spill too much in the bottom of the canoe, hang easily, and double as a solar shower.  Since they pack small, we put them in an easily accessible area and get our water away from shore before arriving in camp.  2 bags are usually enough for a crew of 6 for an overnight stay, unless they are used for showers.