I carry two water bottles.

I use a 2 quart recycled gator aid bottle for my clean water. I carry that in my front bag for ease of access while walking.

I also carry a recycled Christal Geyser (bottled water from Safeway) 1 gallon bottle for dirty water. It has a handle, a wide cap and weighs less than 3 ounces. I've used it for over a year with no leaks. It uses up a lot of room empty or full but I have a large pack so I don't mind.

I have never gone more than 1 day without passing a water source. I do like to dry camp away from people, however, my two bottles allow me to carry up to 1.5 gallons.

I enjoy drinking warm water on warm days. It will stay cold longer, however, buried deep in the pack.....especially if surrounded by closed cell foam.

I once carried fish home from a mountain lake. They were wrapped in snow, plastic bag and closed cell foam. Eight hours later there was still snow in the bag, even though temps had been in 80s.