Water has always been one of the most important resources for a city, and
ancient Rome was famous for its great wealth of public fountains, baths, artificial pools
and reservoirs, naval arenas (naumachiae), irrigation channels, and other
similar facilities. During a time length of over 500 years, eleven main aqueducts, plus a
considerable number of branches, were built for Rome's urban needs.
It has been assessed that, all together, the total output of these aqueducts was
considerably more than the daily amount of water the modern city can rely upon today.
This plenty, which no other place in the world ever had, was worth Rome the name
of regina aquarum, "queen of the waters".
Interestingly, the Romans did not give a name to the aqueducts themselves, but to the water
they carried, so that most of them were referred to as aqua (Aqua Appia, Aqua Marcia,
Aqua Iulia, etc.), often named after the ruler or government officer who sponsored or
presided over their making.
Since the time Rome was founded, the inhabitants could rely on the water of the
Tiber, which ran along the western urban boundary (today it cuts the modern city into two halves),
and on its main tributary, the Aniene, which meets the larger river about 4 km
(2 ½ mi.) north of the earliest city walls, on a spot now surrounded by
During the age of kings, and for some time of the republican age, the population satisfied
its needs by drawing water directly from these rivers, from minor channels, and from a
number of smaller sources such as wells and cisterns for rain water.
In the 4th century BC the size of the city and the growth of
the population, including the many immigrants, the foreign merchants and the slaves, required
a larger supply.
the course of the Tiber and of the Aniene,
compared to Rome's extension in different ages
In fact, in 312 BC
censor Appius Claudius had the first aqueduct built; it drew
water from a spring located between 7 and 8 miles east of the city, although the total
length of its course measured no less than 11 miles (the reasons of such crooked direction
will be explained in part II
The making of the following aqueducts came at an average rate of one every 60 years or so,
but in AD
52 two of them were built almost at the same time.
The length of the aqueducts was expressed in passus ("steps"), a measure corresponding
to 1.482 m or 4 ft 10¼ in). More approximately, they were measured
in milia passus, i.e. roman miles, actually meaning "thousands of steps",
equals to 1.482 km, or 0.92 mi.
The following is a list of the main ancient aqueducts, according to a chronological ordering,
which also shows which parts of the city they served. The location of their springs refers
to the distance and position from the city center, expressed in roman miles.
The rate of flow of each aqueduct was calculated in quinariae. Scholars assessed that
1 quinaria was equals to 0.48 litres/second. The most powerful of the eleven
aqueducts, the Anio Novus, drew 4,738 quinariae, which meant a supply
of almost 200 million litres per day!
Rome's waterworks were supervised by a high officer whose title was curator aquae,
i.e. "water curator". It is thanks to one of these curators, Sextus Iulius Frontinus (late
1st century AD), who wrote a detailed essay on this subject,
that most data concerning the administration, the features and the course of the roman aqueducts
are known today.
The earliest graphic record of these waterworks appears in the Forma Urbis Romae,
an ancient and very detailed city plan dating to the early 3rd century AD,
carved in stone in scale 1:240, some fragments of which still exist. One of them in particular
features an output at the end of a duct, with the word AQVEDVCTIVM.