Archaeologists have discovered remains of underground sewers amid the ruins of Qin, Han, Sui and Tang dynasty cities both large and small. They were made from fired clay, not reinforced concrete as are modern sewers. But when such pipes in these cities were connected one after another, they formed rather comprehensive sewage systems.
今天考古學家在許多秦漢隋唐的大中小型城市遺址中，發現普遍都有下水道遺跡，雖然沒有現代鋼筋水泥材料，管道都以陶土製成，但陶管逐節串連貫通，顯然當時城市的排水已頗嚴密。