Ancient Roman lead pipes found in Ostia Antica.
Ancient Roman lead pipes found in Ostia Antica. Chris 73/CC BY-SA 3.0

The Ancient Romans are known for their vast empire, their politics, and for their impressive public works projects. Parts of their aqueduct, sewer, and pipe system that carried water to residents, and waste away, can still be found. The pipes have long been a source of controversy—it’s been suggested the lead from pipes caused widespread lead poisoning that led to the downfall of the Roman Empire. New research still doesn’t answer that question, but it does tell us the Romans started using lead pipes earlier than previously believed.

Today, the site of Ancient Rome’s harbor city Ostia lies about two miles from the shore, thanks to centuries of silt deposits from the Tiber River. A team of British and French researchers took 177 core samples from the area, then used carbon dating to determine the age of each layer. The layers of soil provide a record of flooding on the Tiber and the buildup of silt, but they also provide a thorough record of the use of lead pipes. The researchers were able to measure the levels of lead in the layers, and found that Romans started using lead pipes around 200 BC, and stopped around 250 AD.

Lead pipes found in Rome by archaeologists so far have date stamps that only go back to 11 BC, but the new timeline for lead pipe use makes sense—large aqueducts were built around 140 and 125 BC and they would have needed an extensive pipe system to deliver all that water to residents. The lead levels dropped during a civil war in the first century BC, and again after 250 AD, when they stopped maintaining their pipe system as their economy declined.