A rescue excavation was undertaken on a site where an industrial warehouse was under construction in the locality of Petraro. This revealed the substantial structures of a Roman water supply system. Several phases of this structure, which presumably served a large nearby villa or was destined for public use, were identified (late Republican – late 3rd century A.D.). The structure comprised large cisterns of successive date, a small channel outside the latest cistern, a terrace wall on the south-western side and, on the opposite side a crudely-built structure delimited by low dry stone walls. The discovery within this area and in the immediate vicinity of a number of pits, some of which interpretable as ustrina of Roman date, confirms the ancient occupation of this area and its undeniable archaeological and historical interest. The earlier of the two cisterns (late Republican period) was an elliptical oblong in plan (9 x 2.50 m). The later cistern was larger (25 x 3.30 m) and had a very elongated rectangular plan, with an apse at each end and was on the same alignment as the earlier one. Both cisterns fit into type 2 (“single chamber and non-communicating parallel chambers”) of I. Riera’s new classification. The long northern side of the two subterranean or semi-subterranean cisterns abutted the hill slope. Both had a vaulted roof. They appeared to have been very carefully built, the earlier one in particular. At present it is unsure whether they were supplied by a branch from the local aqueduct of which traces have been found in the past at various points within the territory of S. Angelo d’Alife, including Petraro. The other hypothesis is that they were used for the collection of rainwater via a filtration basin, that remains undiscovered, buried on the hill.