Just like many other fountains built in the XIII century, the Fountain in via Osmano is incorporated into a building and gives access to a chamber located below the street level, through an archway; entry was possible thanks to a staircase.
At the rear, there was a huge cistern fed by the aqueduct of Prato Baglioni. This channel, which originated from Colle Aperto and ran along the northern side of the hill, ending in the Delfino Fountain of Borgo Pignolo, is today dry.
