The Romans constructed aqueducts to bring a constant flow of water from distant sources into cities and towns, supplying public baths, latrines, fountains and private households. Waste water was removed by the sewage systems and released into nearby bodies of water, keeping the towns clean and free from noxious waste. Some aqueducts also served water for mining, processing, manufacturing, and agriculture.

Aqueducts moved water through gravity alone, along a slight downward gradient within conduits of stone, brick or concrete. Most were buried beneath the ground, and followed its contours; obstructing peaks were circumvented or less often, tunneled through. Where valleys or lowlands intervened, the conduit was carried on bridgework, or its contents fed into high-pressure lead, ceramic or stone pipes and siphoned across. Most aqueduct systems included sedimentation tanks, sluices and distribution tanks to regulate the supply at need.

Rome's first aqueduct supplied a water-fountain sited at the city's cattle-market. By the 3rd century AD, the city had eleven aqueducts, to sustain a population of over 1,000,000 in a water-extravagant economy; most of the water supplied the city's many public baths. Cities and municipalities throughout the Roman 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."