I have found that larger water containers are more prone to problems. Contamination, leakage, UV+plastic=foul taste, metal cans are heavy and awkward, etc. There is an initial investment into the container, and that is lost if the container becomes too dirty or unreliable to use. Disposable containers are good because they can be replaced cheaply, tossed, and forgotten about.
In my experience, lots of smaller sources of water is a better deal. Smaller containers conform to space instead of dominating it. Gerry cans are suitable for washing, refill and treat the water in them minimally if washing small children in foreign countries or high-risk areas. In an emergency, the water can be treated and drank, if unpleasant tasting, still better than severe dehydration.
I prefer that my drinking sources be pre-sealed, in other words I do not like filling containers from the tap. There are too many factors to worry about in terms of contamination, and I have seen even small bottles refilled with clean water become fetid in a few days in the right conditions.
The rule of thumb in the desert is one gallon per person, per day in moderate conditions, and more in less than forgiving conditions. Having opaque containers and large containers can make it more difficult to gauge usage.
So, I buy my drinking water in pre-measured jugs of varying sizes. The only time I refill is to fill small bottles or canteens from larger bottles. In terms of travel reliability and convenience, not all bottles are created equal.
These are square, carry around 2.5 gal. and have a spout (you must poke a hole in the top to bring in air), are completely unsuited for travel. It is leaky, the container lacks integrity esp. in heat, and the type of plastic used imparts the taste of plastic to its contents.
These "wide-mouth" 32 oz. bottles are great. The plastic is heavier duty than the smaller bottles, doesn't impart a plastic taste, and is the size of the standard canteen. One great aspect of these bottles is the wide-mouth. Say it's cold outside, you're all warm and comfy in your sleeping bag, and nature calls. No fear, you have a tent urinal by your side. Unless you're John Holmes, you can fit in there and do your business. Cap it up, throw it out in the morning, and you're done. Just don't go drinking the apple juice!
These are great. They are 1 gal., are made from the same durable, flexible plastic as the small water bottles, can take a ton of abuse without breaking and absorb UV without breaking down in the water. They are measured out well, you can count them quickly by need (one bottle per person per day), and after they're done, they collapse, or have other uses (We use them for measured showers, you get one gallon jug, no mas. I also cut the bottoms off to use as cereal/marinade/mixing/prep bowls). The only thing I don't like about these is you have to keep track of the cap, as they are weak and if slightly unscrewed will leak.
I use these "Sparklett's" type bottles for longer trips or really severe temperatures. The five gallon bottles are heavy, esp. top-heavy; I prefer the 3 gallon size. They are stouter, hardier, and easier to throw around. They can withstand tons of abuse and UV does not ruin the taste. The bottles are often tinted, which keeps them slightly cooler. They have an integrated handle molded in which makes them easier to strap in. The caps, even after being unsealed, are very reliable.
