Short answers, pulled from the story.
Rome's first aqueduct, the Aqua Appia, was built in 312 BC. It was commissioned by the censor Appius Claudius Caecus and supplied a fountain at the city's cattle market, the Forum Boarium, delivering approximately 75,500 cubic metres of water per day.
Roman aqueducts moved water through gravity alone, along a slight but consistent downward gradient. Vitruvius recommended a minimum gradient of 1 in 4800. Where valleys interrupted the route, engineers used either tall masonry arcades or inverted siphons made from lead pipes.
By the late 3rd century AD, Rome was served by eleven state-funded aqueducts. Their combined conduit length included approximately 47 km carried above ground on masonry supports, supplying an estimated population of one million people.
Sextus Julius Frontinus served as curator aquarum (water commissioner) under the emperor Nerva in 97 AD. His official report, De aquaeductu, documented the supply, uses, and abuses of Rome's public water system, including detailed calculations of how much water was stolen and the methods used by fraudsters.
The longest single conduit is associated with the Valens Aqueduct of Constantinople, at over 240 km. It has been described as one of the most outstanding surveying achievements of any pre-industrial society, surpassing the well-known aqueducts at Carthage and Cologne.
Public fountains had first priority in Rome's water supply, followed by public baths, then fee-paying private users. Private access was registered by pipe bore size, with wider pipes carrying higher fees. Personal water grants issued by the emperor could not legally be inherited or sold, though in practice they were transferred regularly.