Well, I Never!
Well-heads are a common feature in most Venetian campi and recall a time, before the arrival of piped water in the 19th century, when rain water was collected in vast underground cisterns. Water was a precious commodity and the well-head was kept locked and only opened for a limited number of hours each day. The key was usually kept by the local parish priest.
Most well-heads were carved out of white Istrian stone, but occasionally Verona marble, a pinkish and much more expensive stone, was used. In terms of the elaborate details of their decoration, many well-heads are exquisite works of art, as we can see in the courtyard of the Ca' d'Oro.