Rome’s first aqueduct was built in 312 BCE. It was built to supply a water fountain at the city’s cattle market and trading center. It was built underground by Appius Claudius Caecus, a Roman magistrate.

Construction of aqueducts continued and by the 3rd century CE, the city had 11 aqueducts, sustaining a population of a million residents in a water-extravagant economy. Their combined conduit length is estimated between 780 kilometers (485 miles) and a little over 800 kilometers (497 miles), with approximately 47 kilometers (29 miles) carrying water above ground, on masonry supports. They supplied 1 million cubic meters of water (300 million gallons) a day.

Most of the water supplied the city’s many public baths. Additionally, the aqueducts supplied latrines, fountains, private households, supported mining operations, milling, farms and gardens.

As the Roman Empire expanded, cities and towns throughout the empire emulated this model and funded aqueducts as objects of public interest and civic pride, “an expensive yet necessary luxury to which all could and did aspire.” In the publication called the ‘Roman Antiquities’ Dionysius of Halicarnassus writes, “The extraordinary greatness of the Roman Empire manifests itself above all in three things: the aqueducts, the paved roads, and the construction of the drains.”

Roman aqueducts proved reliable and durable; some were maintained into the early modern era, and a few are still partly in use today.

More Info: en.wikipedia.org