NICOPOLIS AD ISTRUM. CASTELLUM AQUAE (Ivan Tsarov – tsarov@abv.bg) The lead pipes from the water-conduit system of the castellum aquae were looted during the Ottoman and the Early Modern periods. Four water-conduits of terracotta pipes were discovered. They were constructed after AD 325 – 350, when the aqueduct was already in exploitation for more than two centuries and its technical condition was bad. Some of the terracotta pipes had spiramenes closed with circular terracotta caps. The two buildings situated to the north and to the south of the water-conduits were partly excavated. A layer of fragmented tegulae and imbrices from the collapsed roof was discovered in the southern building.