The early years of Roman Plumbing
If one wishes to move water from a higher to a lower location, water will deliver its own transport through gravity and with a channel to flow in. This was the principle behind water engineering in the Roman Empire.
But why did the Romans build these aqueducts to the city of Rome itself, from as far away as 50 miles (80 km) from Rome?
Like many great cities, Rome was established around a river. And even at the time when no one knew about bacteria, it was well known that spring water was better than river water. When the river was as low between the hills of Rome as the Tiber goes in Rome, a lot of muscle power had to be used to carry water from the river to the dwellings. On top of this were the grander elements of Roman aquaculture, requiring water for springs, public baths and gardens.
Arcades of stone were built on top of a row of tall columns, also in stone. The actual water channel/pipe was situated on top of these arcades. The channels were made from concrete, often with a vaulted or angled roof above it. When an aqueduct had to cross a particularly deep valley you had to build several rows of arcades on top of each other. Such structures can still be seen in Segovia in Spain and Nimes in France.
At the end of the aqueduct-building around 100 AD, the combined length of all the aqueducts to Rome was around 300 miles/500 km, of which only 30 miles/50 km were on arcades. Hardly any of the pipes and channels in the aqueducts were under pressure.
This first century after Christ was also the first period of regulation and of the regulator of all regulators, Rome´s curator of water Sextus Frontinus. Frontinus employed 700 people, from civil engineers (as opposed to military engineers) , surveyors, masons and pipe layers (aquiarii) .
In his famous report De aquis (https://en.wikipedia.org/wiki/De_aquaeductu) there is a list of how various groups of citizens had broken the water regulations.
- Withholding of water taxes for own purposes procurators:
- fraud with wrongly stamped connection sizes the pipeline connectors
- illegal pipe dimensions
- cross connection of pipes from two aqueducts
- general incompetence and dishonesty
- use of unstamped connections
- puncturing of main pipes/channels
- hindrance of access for regulator staff
- planting of trees around the foundations of the arcades
An estimate has been made of the water supply to Rome in its heyday, based on volume of the nine aqueducts. The population of Rome was enormous for the period, around 1 million. But even when considering waste, theft, unauthorized connections and aqueducts under repair it is estimated that each inhabitant would have available 300 to 400 litres per day. Much of the supply was unregulated running water to the public baths and fountains. But there was at least a regular daily supply of 150 litres per inhabitant in the city of Rome.
The water supply
Every aqueduct had its reservoir where it reached the city, and where impurities could settle. Some aqueducts were designated to deliver potable water, others to supply water to the latrines and the gardens. From the reservoirs, water was led in zones to a row of castellums (small towers) equipped with cisterns in lead. From Pompeii we know that these castellums were approximately 6 metres tall. In the vertical wall of the cisterns there were outlet pipes in three heights. The upper one would supply water to the fountains but only when water was plentiful. The middle outlet would supply the public baths, and the lower outlet would supply the public ”flat running wells” which were often richly decorated
Lead pipes were used almost universally in the city of Rome. The pipes were made from sand cast lead sheet, formed oval around a mandrel and then butt-soldered. To avoid high mains pressure the pipes were continuously led to new cisterns and fed by gravity from there. In reality there was only pressure (6-12 metres) in the pipes from the cisterns and out in the streets. Every lead caster (plumbarii) cast his name in his own pipes, an early QA documentation. The caster would also lay the pipes and was thus the first plumber.
The historian Vitrivius wrote (The ten books of Architecture, book VIII) that exaggerated use of water from lead pipes was unhealthy ”water is much healthier from clay pipes than from lead pipes. Water gets polluted by lead. We can see this in the lead casters (plumbarius). When they cast their pipes the vapours from the lead enters the body limbs, and removes the advantages of the blood from the limbs”.
Against this statement it must be said that the water was from springs and constantly flowing, and that a protective layer of calcium was formed inside the pipes. This has later been confirmed by archaeological finds.
If you had no water pipes leading into your house nor time to collect water you would let your water carriers (aquarii) do this task . These aquarii were attached to the individual houses and would stay with a new owner if a house was sold.
The public baths
Around 200 BC, public baths were starting to be built in Rome. You combined the original purposes with private baths – cleanliness – with elements from the Greek gymnasiums. Around a central hall there would be rooms with steam baths, warm baths and cold baths, gambling places, gardens and even libraries.
The philosopher Seneca lived just above such a bath. He wrote about the noises”... the slapping from the masseur’s hand, the grunts from the weightlifter struggling with his dumbbells, the screams from the man having hair picked from his armpits, the splashing of the swimmers, the shouting from the vendors of sausages, cakes and other morsels ...”
The unwanted water
Just as you built aqueducts to lead water into the city, drains and sewers were being built to remove the unwanted water. The sewerage system of Rome was started around 300 BC. First a trench was dug to drain the swampy area around the seven hills. The first trench followed an existing stream, and a bricked channel was built to lead away the rainwater.
Later generations expanded and improved the channel and covered with concrete blocks and rainwater grids, and later people also lead waste water to the channel. This channel became the large Cloaca Maxima built from rock - for centuries could row through in a boat.
Later extensions to the sewerage system were combined with connection to public latrines, simply being built along with and on top of the channels.
These latrines were lavishly decorated , and when many centuries later such a latrine was being unearthed, it was first thought to be a place of worship. In reality it was so, a temple for wellbeing and public health.
The latrines were also public in the sense that this is where you arranged to meet. They were the cafés of their time, where one conversed, and where one without embarrassment would exchange invitations. The seats were made from marble, and the openings formed like the mouth of a dolphin, providing both support and demarkation . Above the seating you would have statues of Roman gods and heroes , and in the middle there would often be an altar for Hygieia, the goddess of cleanliness and hygiene.
When brown and yellow were ”green”
Many Roman citizens would have a latrine tank in their house, which was emptied when required by the local manure merchant. He collected the contents in his cart and sold it to the farmers around Rome to be used as natural fertilizer. Thus the Romans contributed to the natural circuit by taking form nature and giving back to nature.
The sanitary system of Rome was very advanced . When The Chadwick Commission in 1842 had to recommend ways of improving health and sanitation for the people of London, a description of the sanitary installations of Colosseum was included in the report. These were in the year 150 AD superior to the installations in London 1700 years later.
Benny Wielandt, Technical Education Copenhagen (retired) email: firstname.lastname@example.org