<P> The Romans constructed aqueducts throughout their Empire, to bring water from outside sources into cities and towns . Aqueduct water supplied public baths, latrines, fountains, and private households; it also supported mining operations, milling, farms, and gardens . </P> <P> Aqueducts moved water through gravity alone, along a slight overall downward gradient within conduits of stone, brick, or concrete; the steeper the gradient, the faster the flow . Most conduits were buried beneath the ground and followed the contours of the terrain; 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, which helped reduce any water - borne debris . Sluices and castella aquae (distribution tanks) regulated the supply to individual destinations . In cities and towns, the run - off water from aqueducts scoured the drains and sewers . </P> <P> Rome's first aqueduct was built in 312 BC, and supplied a water fountain at the city's cattle market . By the 3rd century AD, the city had eleven aqueducts, sustaining a population of over a million in a water - extravagant economy; most of the water supplied the city's many public baths . Cities and towns 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". </P>

What force did the romans use to move water