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The Romans, whose city was surrounding by marshes at the first times, took from the Etruscans the custom of evacuating water from the cities because the water became uncomfortable and unhealthy; so it was necessary to make canalizations that evacuated the residual water and drained the city.  At the same time, these canalizations built to remove residual water, in their origin were a way to drain the marshy zones near Rome to increase the fertile and inhabitable lands around the Roman hills; they were very useful to reduce illnesses like the malaria and some kind of fevers.

The primitive system of canalization was not efficient, because it was filled up with residues at once –after some time the Romans had problems to evacuate all the water used in the city-; in addition, only a few sewers were connected with the central system of evacuation; so they run off in cesspools; from these cesspools some gases emanated, such as methane or sulphide of hydrogen that produced bad smell and explosions; moreover, when the Tiber river suffered a flood, the sewers were not capable to drain the residual water; in fact sometimes the water from the river could overflow the sewers.




At the first times, the Romans used channels in the open air and cesspools, but alter that they used cuniculi, i. e., galleries similar to rabbits’ galleries, because they thought that they imitated these animals, digging out galleries in different levels, extracting the rubbish, using the galleries to clean and ventilate their dens and creating real labyrinths.  Normally the Romans started the channel in a hill and with a light pitch the channel reached a valley or a river; in Rome the primitive cuniculi reached the Tiber river from the Viminal and Esquline hills.  The technique to make cuniculi was similar to the technique to make specus in the aqueducts.  The first big sewer in Rome, attributed to Tarquinius the Ancient (Lucius Tarquinius Priscus), was used to drain the lands more than to drain the city; in a first moment it was a channel in the open air –in the II century b. C. still kept uncovered- that crossed through marshy districts and drained them; with this drainage Rome extended to the later Forum and Velabrum, districts where there were an enormous trade activity.  In 520 b. C. Tarquinius the Superb renewed this channel, 800 metres long, burying it and recovering it with vaults.  The work must have been very important, because it received water from the river floods and from rushing streams, while it drained the residues of these parts of Rome.  An important fact that we cannot forget is that it is necessary a steady water stream to drain and evacuate water, because the stream pull the residual water; so, after the building of aqueducts in Rome, the evacuation depended on the rain water and the water from fountains and the system was very often interrupted.




The Cloaca Maxima –“the greatest sewer- arose from the Tarquinius’ work; this sewer was a restructuring of a labyrinth of drains and galleries to adapt the sewer system to the growing city.  The construction of the Cloaca Maxima was such a big work that it remained in the tradition as something enormous and legendary.  When the Gallics destroyed Rome in 390 b. C., this sewer subsisted without any problem, but in the rebuilding of the city the new plan of houses and streets changed so that the sewers that were under the street then were under the houses.  During two centuries from the construction of the sewer only maintenance and clean works were made, but after building aqueducts that increased the water flow in the city and, at first, helped to drain residual water –this happened in 312 b. C. with the aqua Appia-, however it was necessary to restructure completely the sewer system, because it could not drain all the water –this happened in 272 b. C. with the aqua Anio vetus-: the cuniculi in districts with new fountains became excessively wide and insufficient to evacuate the residues.  So the system was restructured and the Roman planned new increases of flow from other aqueducts, like it happened in 144 b. C. with the aqua Marcia.  The remains of the Cloaca Maxima that now we can see are dated at the end of the Republic and in the age of Agrippa, since 33 b. C., when the sewer was completely rebuilt.  From this period an underground gallery, 5 metres diameter in some sections, is preserved (the known dimensions indicate that the Cloaca Maxima was 900 metres long, 4,20 metres high in some sections and 3,2 metres wide in average); arches with superimposed keystones on the Tiber river and a low and solid vault are preserved too.  Ancient testimonies informed us that a wagon loaded with hay could be contained in it and Agrippa sailed through it in a small boat.  Then, after the building of two new aqueducts, Agrippa ordered to divert the flow of seven small rivers to this sewer, remade its walls and vaults in the zone of the Forum Boarium and opened new channels in the Campus Martius.  So, after the emperor Augustus, Rome had three sewer systems: the first, the Cloaca Maxima to drain the Forum and its area; the second, in the north of the Forum, in the Aventine and Palatine hills; and third, in the south of the bridge Rotto that drained the Campus Martius.  These three systems had a central collector from which small galleries –called cloaculae- went out.


Vault y main drain of the Cloaca Máxima (Photographies from CONNOLLY, P. y DODGE, H., La Ciudad Antigua.  La vida en la Atenas y Roma clásicas, Madrid, 1998)




However, Rome and the other cities in the Empire were not clean cities, because the sewerage did not reached all their corners.  The sewers collapsed down due to the weight of the buildings, vehicles, roads, etc., and they suffered the sliding of the grounds due to their permeable nature or to earthquakes; in most of the cities the sewerage did not reached some quarters –in the Roman Trastevere (from the Latin trans Tiberim, “across the river Tiber”) there were sewers only since the year 109 a. C.-.  That is why a large number of Romans were obliged to collect their rubbish and to store it; nevertheless, the Romans threw very frequently through the windows to the streets, especially in the night, and sometimes private companies put deposits where they collected this rubbish to sell it and to use it like fertilizer.


The Cloaca Máxima in Rome in the Forum Boarium

(Photo: Roberto Lérida Lafarga 27/12/2004)




When the Romans tried to make a sewerage on a large scale and in the different cities along the empire, at first they made irrigation ditches and small channels near the sidewalk, where the water filled of rubbish flowed; these channels came together outside the city and evacuated the residues in a river, in the sea or in a field like irrigation water (including the fertilizer).  However, in the I century a. C. it was inconceivable that a city had not got a sewer system that drained it.


Reconstrucción del sistema de alcantarillado de Roma (Photography from CONNOLLY, P. y DODGE, H., La Ciudad Antigua.  La vida en la Atenas y Roma clásicas, Madrid, 1998)




The sewerage was exported by the Romans to all the cities along their empire, sometimes in a medium or large scale.


Cloaca de Vasio (hoy Vaison la Romaine, Provenza, Francia)

(Photo: Roberto Lérida Lafarga 6/8/2007)


In Aragon, among the archaeological remains of the forum of Caesar Augusta (nowadays Zaragoza) we can see two sewers very well preserved: the first one, from the age of the emperor Augustus, had a modest size (1,28 x 0,90 metres); on the other hand, the second sewer, from the age of the emperor Tiberius, as a general collector of residual water from all the network of sewers of the city, had a larger size  (2,82 x 2,20 metres) and it is preserved in a large section (about 40 metres).


Large sewer from the age of Tiberius almost under the cardo maximus in the forum of Caesar Augusta.  (Photo: Roberto Lérida Lafarga 28/04/2008)


Sewer from the age of the Augustus under the forum of Caesar Augusta. 

(Photo: Roberto Lérida Lafarga 28/04/2008)


View of the two parallel sewers in the Museum of the Forum of Cesaraugusta.

(Photo: Roberto Lérida Lafarga 28/04/2008)







- MALISSARD, Alain: Los romanos y el agua: La cultura del agua en la Roma antigua, Barcelona, 1996

- BELTRÁN LLORIS, Miguel: “El agua profana en la cuenca media del valle del Ebro:  AQUA DUCTA.  La captación del agua, presas, embalses, conducciones”, en AA. VV.: Aquaria: Agua, territorio y paisaje en Aragón, Zaragoza, 2006

- CONNOLLY, P. y DODGE, H., La Ciudad Antigua.  La vida en la Atenas y Roma clásicas, Madrid, 1998