A visit to Pompeii’s public baths initially involved immersing oneself in water tainted with bodily fluids, a situation that significantly improved once Roman rule was established and sanitation practices advanced.
It is tempting to view ancient Pompeii as a quintessential Roman settlement, especially considering its geographical proximity—approximately 240 kilometers southeast of Rome itself. However, for a considerable duration of its history, Pompeii was inhabited by the Samnite people, who maintained a distinct cultural identity. It was not until after 80 BC that it transitioned into a Roman colony, a mere 160 years before the city was engulfed by volcanic ash following the eruption of nearby Mount Vesuvius.
Similar to the Romans, the Samnites appear to have held a strong appreciation for bathing rituals. They constructed at least two public bath complexes, now identified as the Stabian Baths and the Republican Baths, sometime after 130 BC.
Insights into Water Quality from Mineral Deposits
Gül Sürmelihindi, affiliated with the University of Mainz in Germany, and her research team have recently undertaken an analysis of mineral deposits found within these bathhouses. Their objective was to gain a more precise understanding of the water quality that once filled the bathing pools.
The findings suggest that the water quality left much to be desired. Sürmelihindi notes, “Water in the hot pool of the Republican Baths exhibited low stable carbon isotope values, which points to the presence of substantial organic matter.”
Crucially, when the researchers examined mineral deposits taken from the 40-meter-deep wells that supplied the pools, they discovered a scarcity of organic matter. Sürmelihindi explains that this indicates “the contamination must have occurred within the pools themselves,” primarily from bathers’ sweat, the oily sebum secreted by the skin, and even their urine.
The researchers propose a likely reason for this. The process of drawing water from these deep wells, employing a system of buckets, was both slow and physically demanding. They estimate that only between 900 and 5,000 liters of water could be extracted per hour. This volume was insufficient to do more than refresh the bath water once or twice daily.
Roman Intervention and Improved Sanitation
The situation underwent a transformation under Roman administration. Within a few decades, the Romans had engineered an aqueduct designed to deliver water to Pompeii, sourced from natural springs located approximately 35 kilometers northeast of the town. Sürmelihindi observes, “We get the impression that constructing an aqueduct was a priority, but also a matter of prestige: if one city possessed one, others would naturally desire the same.”
The researchers calculate that the aqueduct provided Pompeii with an impressive 167,000 liters of water per hour. This volume was ample for considerably more frequent replenishment of the public baths, in addition to supplying Pompeii’s inhabitants with a new and readily accessible source of drinking water.
Supporting the notion of enhanced hygiene in public bathing, Sürmelihindi and her colleagues identified that mineral deposits found in the Roman-era drainage systems of the Stabian Baths contained significantly less organic carbon. This suggests that the concentration of sweat and urine within the water was substantially reduced due to the more frequent circulation of bathing pool water.
Potential New Health Concerns: Lead Contamination
However, the advent of the aqueduct does not automatically equate to an improved health outcome for the Pompeiians. Prior to its construction, the majority of the populace consumed rainwater collected in tanks connected to the city’s building rooftops. Following the aqueduct’s completion, many individuals obtained their drinking water from this new supply via an extensive network of lead pipes that traversed the city. Lead, a known toxin capable of causing neurological damage, could leach from these pipes into the water supply.
Although lead contamination should theoretically diminish over time as mineral deposits gradually form a coating on the interior of the pipes, thus reducing direct contact between the water and the lead, some researchers hypothesize that lead contamination levels could have surged anew whenever sections of the city’s plumbing underwent repairs involving fresh piping.
Duncan Keenan-Jones of the University of Manchester in the UK suggests, “Pompeii’s elite were likely in a better position, as they resided in homes featuring large atria with inwardly sloping roofs that directed rainwater into a cistern. Poorer individuals, possibly living in their shops, were more dependent on the lead-contaminated water from street-level fountains.”