A lovely detail of life in ancient Rome still survives today. Nasoni ("nose" in italian- they do look like big schnozzes, don't they?) are fountains found on many a street corner. The water is public, free and potable, a rarity in many European cities. We filled our water bottles at these fountains many times and it was nice to see tourists and locals both making use of them. (And fun to imagine someone in a toga doing the same thing fifteen hundred years ago!)
I think big water bottles are one of the biggest giveaways that you are a tourist (and an American), but without them it's hopelessly difficult to stave off thirst, especially since ordering it in a restaurant means a 2 euro charge (or a huffy little scene with a waiter. Take your pick.) How do Europeans manage to drink all that espresso and wine without hauling bottles around in their bags like us tourists? Nasoni help to unravel the mystery, but I'll keep you posted on my other findings.