The Valens Waterway system and the aqueduct bridge were completed in 373 during the reign of the emperor after whom it was named: Valens (r. 364-378).

According to Cedren and Zonaras (c. 11th century), the aqueduct bridge may have been built with material from the walls of Chalcedon that were torn down after the revolt of the usurper Procopius (r. 365-366) against Valens. Müller-Wiener (1977) considers this unlikely and unreliable.

The new Valens line drew upon new and more distant sources: 1) the highly-elevated springs at Halkalı and later 2) the springs near Vize (ancient Bizye, 250 km from Constantinople) in Thrace called Danamandıra and Pınarca.
The Valens aqueduct bridge thus may have carried water from both Halkali and Vize simultaneously through its two-levelled channels. Even though Halkalı’s waters were hard and not as desirable as distant Vize’s, they may have been the only highly-elevated sources that could provide the highest city parts during the late Byzantine and Ottoman period when the Thrace line fell out of order (Crow et al. 2008, p. 120).