The Roman aqueducts were a multi-step system for bringing water from a distance to Roman cities and from there to distribute it. The aqueducts began as stone, brick or volcanic concrete channels that carried water at a slight downward slope from their source, and from there the water ended in catch-basins for the purpose of allowing sediment in the water to settle.
Surprisingly most of the channels leading to the catch-basins were underground; of the 260 miles of channels there were only approximately 30 miles above ground. The channels above ground were there due to the need to adjust the slope to ensure the steady flow of water made possible by gravity.
When low areas were in the water’s path, viaducts were built for the water to cross without losing the gentle slope needed to make the water run properly. From the catch-basin, water continued via canals and pipes, built of lead and terra-cotta until reaching storage reservoirs called castellan (cisterns). The castellan were located at the highest points in Rome so that homes, bath houses, and fountains could received water from lead pipes connected to these cisterns.
Not only did the ancient Romans bring water to their cities, but they arranged for its departure as well with sewers known as cloacae. For the construction of the cloacae it was necessary to go through Rome's seven hills to transport the waste water to the Tiber River. It is believed at the height of the empire 500 thousand barrels of water were piped into the city and sent through the cloacae every 24 hours.
A theory that Rome’s decline came about from the result of lead poisoning is no longer considered a viable one; Rome’s water did go through lead pipes but was always moving and would have been unlikely to become tainted. In addition, the water they carried was hard, meaning it contained dissolved minerals, which left deposits inside the pipes after a few years and prevented the water from coming into contact with the lead.
The aqueducts enabled the Romans to live a life that was luxurious to a degree almost unimaginable for their time period. The steady supply of safe water for drinking and bathing went a long way to prevent the diseases that decimated cities centuries later that were without water and sewage systems to equal Rome's. The aqueducts were so important that their destruction by the Goths in 537 AD was the death blow to the city.