The monumental fountain (nymphaeum) is located in a north-west area of the thermal complex. It is an imposing fountain consisting of an apse basin of rectangular shape, with four angular pillars that perhaps supported a cover. The fountain seems to have been built by overlapping with an existing structure. Behind it, the excavations brought to light the presence of five large rectangular tanks that constituted a water reserve not only for the operation of the fountain, but also for the needs of the villa.