This rare hydraulic fountain dates back to the 13th or even 12th century. Of Romanesque design and careful construction, its six semicircular arches support a broken barrel vault. The basin collects the water emerging at the lowest point of the city, from where its name of Lower or Covered Fountain.

It may have originally belonged to the Knights Templar, but after their dissolution in 1309, it was returned to the Cistercians to irrigate their nearby gardens.

A small wash-house was added in 1770 next to the reservoir. The building was restored in 1997, when it was also classified as a historic monument.