In the warmer months throughout Switzerland there are drinking fountains with continuousy running water, over the last 50 years when visting Switz. I've imbibed with no ill affects. [Particularly in Zermat, the cold moutain water is really nice!]
Swiss fountain water is probably my favorite water in the world. There's nothing like it!
More directly related to the topic at hand, I don't know what it is but there is something about me and islands. I know beforehand that the water treatment facilities aren't up to the level of the big cities and so I take extra precautions, but still I always manage to get into something anyhow. Central America, Southeast Asia, Europe, no matter, as soon as I step off the mainland I almost always am struck down eventually!