New Research Exposes the Good and the Gross in Pompeii’s Baths

Right after their famous roads and imposing gladiatorial arenas, the ancient Romans are perhaps best known for their public baths and enduring aqueducts. New research sheds light on these structures in one of their most iconic sites: Pompeii.

In the first century CE, one of the most infamous ancient tragedies immortalized the Roman city of Pompeii. Among many things, it preserved some of its residents in their final moments—down to the weave of their clothing—as well as the city’s water system. In a study published today in the journal PNAS, researchers investigated the ancient city’s water supply via geochemical analysis and archaeological due diligence. Differences in the calcium carbonate deposits found in the water-bearing structures reveal the origin of the water and shed light on Pompeii’s bathing culture.

Crusty remains

“Carbonate incrustations [were] deposited in various components of the city’s hydraulic infrastructure, including the aqueduct, its water towers, the well shafts, and pools of the public baths,” the researchers, including the University of Mainz’s Gül Sürmelihindi, wrote in the paper.

A hot bath at Pompeii’s Stabian baths. © Cees Passchier

Calcium carbonate is a chemical compound, and its deposits in Pompeii’s public baths, wells, and aqueduct can unveil shifts in the water’s quality, origins, and quantity across time. According to the study, deep wells originally served the ancient city’s industrial areas and public baths. The Romans employed human-powered equipment to pull up water from wells with up to 131-foot-deep (40-meter-deep) shafts.

“The ancient city of Pompeii, destroyed by the eruption of Mt. Vesuvius in AD 79, shows technological improvements to its water supply after becoming a Roman colony. Its inhabitants relied on wells for their water supply prior to the installation of a Roman aqueduct,” the team explained.

Deposits that have endured in the Republican Baths, for example—constructed in the second century BCE and abandoned during the following one—unambiguously pointed to the presence of pollutants caused by human activity. This indicates that Romans did not consistently refill the baths’ water. Yeah, gross. An aqueduct later offered a more fixed water supply, allowing bathing structures to grow and probably ameliorating hygiene.

Wells versus aqueducts

“While the aqueduct was fed by karst springs, the wells tapped into highly mineralized groundwater from volcanic deposits,” the researchers wrote. “These geochemical distinctions allow for a detailed reconstruction of Pompeii’s water management system, particularly the transition from well- to aqueduct-based water supply.”

Among the ruins’ gorgeous frescoes and heartwrenching human voids, the study sheds light on an often-overlooked part of ancient Roman life: the infrastructure that kept its culture running. And speaking of overlooked aspects of Pompeii, did you know the ruins were inhabited for centuries after the eruption?