completed by his successor Claudius; the 69 km Aqua Claudia, which gave good quality water but failed on several occasions; and the Anio Novus, highest of all Rome's aqueducts and one of the most reliable but prone to muddy, discoloured waters, particularly after rain, despite its use of settling tanks.

Most of Rome's aqueducts drew on various springs in the valley and highlands of the Anio, the modern river Aniene,