I always carry my First Need water filter with me (filters out cysts, bacteria, viruses, chemicals and gunk). I came into bicycle touring from a backpacking background, where I would spend my time far, far away from any convenience stores. However, the filter is great for touring and allows me to get water anywhere I see the wet stuff.

Many times I will use drinking fountains or sinks in parks, but anytime there is a danger of freezing they shut the water off here. I like to have the filter for convenient, safe water access and it allows me to stay out in the wilds much longer.