We sometimes hear how the Roman Empire used lead in its water pipes, and as the use of aqueduct water became more and more prevalent towards the end of the Empire, that gradual lead poisoning may have had some influence in the Empire's fall.

But I remember reading somewhere (unfortunately, I don't remember where) that Roman engineers were well aware of the health hazards of lead. I recall that a fragment of one of their engineering treatises survives, and the writer comments on the fact. He warns that although lead pipes have many advantages, that the use of ceramic pipes was preferred because the water delivered was more wholesome. In other words, if you could afford clay pipes, they gave you healthier water. Lead was cheaper in the long run because lead pipes required less maintenance, less frequent replacement, and could be more easily bent into complex shapes. From this we can deduce that lead was used for the poor, and public water works, but the rich put in clay pipes in their villas.