Augustus built at his own expense an aqueduct, known as Aqua Iulia, for Capua, located in today’s Campania region of Southern Italy, which was in Roman times one of the most important civitas of the empire. The course of this aqueduct and of its likely branches destined to two small towns, Saticula and Calatia, is hypothesized, in part based on the re-use, in the seventeenth century, of about 8 miles of the ancient aqueduct for another water supply to serve Naples, namely the Carmignano aqueduct. Then, it is described the subsequent transformation, in the eighteenth century, of the new water supply along a new route at a higher altitude, in a third water supply to serve the Bourbon royal palace of Caserta, a magnificent construction built in the same years. In short, the historical evolution of the Augustan aqueduct of Capua is discussed in the framework of the served communities and of the organization and history of the territory crossed, so showing the richness of information that may be obtained by an integrated study of the transformation over time of an important water infrastructure