The archives available today have been preserved thanks to the efficiency of the American Ulen and the Hellenic Water Company. This corporate culture seems to have been transmitted down the various phases of the company's development in its present form as EYDAP. The result is a rich Historical Archive that contains more than 2,530 negatives and photographs and 2,600 technical drawings, along with a film record of all the successive stages of the construction of this complex technical project that was realized during the interwar period. The EYDAP Historical Archive preserves a variety of items, which reflect the long history and successive operation of the Company (through the "Hellenic Water Company" of Athens and Piraeus and the "Greater Athens Sewerage Organization"), as well as the rapport between the development of the water supply and sewerage system and the evolution of the Athenian society. The Department of Corporate Responsibility & Historical Archive is responsible for the collection, storage, management, and exploitation of the Historical Archival Material of EYDAP. It belongs to the Communication & Corporate Affairs Division. The project of the collection and maintenance of the Historical Archive is part of the actions of the Cultural Network of EYDAP. The Cultural Network reflects the wider effort of EYDAP, for the development of a uniform identity and culture that will produce actions promoting its history and fueling the networks of society with educational and cultural services and provisions.