Technology
The ancient Romans also had a complex system of aqueducts, which were used to transport water across long distances. The first Roman aqueduct was built in 312 BCE. The eleventh and final ancient Roman aqueduct was built in 226 CE. Put together, the Roman aqueducts extended over 450 kilometers, but less than seventy kilometers of this was above ground and supported by arches.
History of municipal treatment of drinking water
Throughout most of human history the primary means of acquiring untainted water was to avoid the problem and bring in water from an outside source that did not require treatment. The Romans did this with their aqueducts. London's New River was constructed, beginning in the early 17th century as a means of bringing in clean water from outside the city. The New River was slow flowing, which helped to increase sedimentation. It also had screens installed every few miles to catch any debris and weeds. These screens required periodic maintenance and workmen were employed to clean them and cut back the weeds. The new river would meet London's needs well enough that there were few complaints before the 19th century, although the water supplied was rarely used for drinking directly, rather it was more likely used for washing or the brewing of beer.