The Aqua Appia, Rome's first aqueduct

For 441 years after the founding of the city, Frontinus wrote, the Romans made do with water drawn from the Tiber, from wells and from springs, some of which were believed to heal the sick. In 312 BCE the censor Appius Claudius, later called the Blind, brought in the city's first aqueduct. He was the same man who built the Appian Way from the Porta Capena to Capua. His fellow censor Gaius Plautius, who found the springs, was given the name Venox, the Hunter.

The intake lay on the Lucullan estate, between the seventh and eighth milestones of the Praenestine Way, 780 paces to the left of the road; the springs themselves have never been identified with certainty. The channel ran 11,190 paces to the Salinae at the Porta Trigemina. All but 60 of those paces were underground, and only the short stretch near the Porta Capena rode on substructures and arches. It was the lowest-lying of Rome's aqueducts. Platner and Ashby put its supply at 1,825 quinariae, or 75,537 cubic meters a day.

Plautius gave up the censorship within eighteen months, expecting his colleague to do the same, so the aqueduct bore the name of Appius alone. Appius is reported to have used various subterfuges to stay in office until both the road and the aqueduct were finished. Augustus later added a branch, named Augusta, that joined the channel near Spes Vetus.

By the time the emperor Nerva made Sextus Julius Frontinus water commissioner, nine aqueducts ran into Rome: the Appia, Old Anio, Marcia, Tepula, Julia, Virgo, Alsietina, Claudia and New Anio. Frontinus wrote that his office concerned the convenience of the city and also its health and even its safety, and he set these indispensable structures against the idle Pyramids and the useless works of the Greeks.