(Elevation: 275 meters above sea level) - This fountain existed already in 1226, but it had fallen into disuse in the following century because of its out of the way location. Also contributing to its abandonment was its reputation for being cursed, either for its location in a dark and gloomy valley, or for being so disgracefully neglected. Initially it was located outside the city walls; its name was derived from the word fullones, that is the fullers and dyers of wool. Its name appears among the those fountains mentioned in the Biccherna, the city account books, and in the medieval period it had plenty of water and was well maintained. It was fortified along with Fontebranda and Fonte Pescaia in 1270, after the winning the battle of Monteaperti in order to prevent its becoming the object of enemy retaliation. At that same time a basin for laundry was also constructed, but it was often filled with earth eroding from above. Fonte Follonica was damaged after the plague of 1348, and fell increasingly into disuse, in proportion to the falling population of that part of the city, and because other, more convenient fountains were being built in the center of the city. It sank deeper into the earth and at the instigation of Pandolfo Petrucci was entrusted to the Friars of Santo Spirito in 1509 and thus removed from public service.
Today the fountain is reduced to a ruin, mostly buried in the earth. However, in the next few years it will be excavated and restored after centuries of abandonment.