The Aqua Marcia was built in 144-140 bC and named after its builder, Quintus Marcius Rex. With this waterworks, built in 4 hard years, people were provided with water of a better quality. Also the distribution had improved. A special technique was used building this aqueduct (reversed siphon), now they could ''conquer" a valley. At the end of the first century bC they increased the water supply by building other aqueducts, the Aqua Julia and the Aqua Virgo (by 33 bC the arches of Aqua Marcia supported the Aqua Tepula and Aqua Julia as well; see drawing).

These aqueducts were constructed by Claudius and Nero in view of the water supply of the higher districts, that still had a shortage of water.

The aqueducts built by Claudius and Nero had more style. The Aqua Claudia, an aqueduct built in 38-52 bC and named after the emperor Claudius provided Rome with water from a source 75 km away; it had a decline of 250 m. This meant that the aqueduct could only descend 1 m each 280 m of lenght. Most of the Roman aqueducts were below ground. The Aqua Claudia i.e. was only 15 of its 70 km above ground.                       v

In a given moment of time 11 waterworks lead to Rome; until the Goths cut down the water supply in 537.
A few were restored by pope Nicolas V in the middle of the 15th century (by the way, the Aqua Virgo remained in service because this aqueduct was totally built underground! See to the right; the same that still feeds the Fountain of Trevi; click the picture for information on fountains). 

The buried arches of the Aqua Virgo in central Rome