What Roman aqueduct was the first built in Rome, constructed in 312 BCE?

The first aqueduct built in Rome, constructed in 312 BCE, was the Aqua Appia.

The censor Appius Claudius Caecus commissioned the Aqua Appia in 312 BCE, during the Third Samnite War. The same year saw construction of the Appian Way, linking Rome toward Capua; both projects strengthened Rome’s infrastructure and strategic reach.

Much of the Aqua Appia ran underground, unlike the dramatic elevated arches often associated with Roman aqueducts. Its water entered Rome from springs outside the city and was distributed through a network of reservoirs. The aqueduct was named after Appius Claudius, although his co-censor Gaius Plautius Venox helped identify the springs.

The Aqua Appia was eventually superseded in importance by later aqueducts, including the Aqua Marcia, Aqua Virgo and Aqua Claudia. By the end of the 1st century BCE, it had ceased functioning as a normal aqueduct and was reportedly used as a sewer.