Carrying water during touring? The earlier question, here, raised this question about carrying water.

How do you carry water during touring? Do yo carry it in panniers, water-bags, bottles, containers or elsewhere? How does your carrier change in different location. You can see from earlier question that it is not trivial to get even clean water. So it sounds logical to carry a lot of water when you are in locations where water can be tight. In such case, when you get the water perhaps bottled water. How do you allocate it? Have you never thrown something away because you needed more room for water?
I have used old wine cask bags (or bladders, readily available in Australia, not too sure about rest of the world) packed either into a pannier or strapped onto the top of the rear rack (not the best position but I was fully loaded).  Some would say the slight after taste of wine is a bonus.  I have also seen unused bladders available from some camping stores.

I also have carried water purification tablets just to be safe.