Which Aztec emperor built the first aqueduct to Tenochtitlan?

Moctezuma I built the first major aqueduct supplying fresh water to Tenochtitlan.

During his reign, Moctezuma I organized the construction of the Chapultepec aqueduct, which carried spring water from Chapultepec to the island capital. The project is also closely associated with Nezahualcoyotl, the ruler of Texcoco, who helped design or engineer it. Thus, Moctezuma I was the emperor responsible for the work, while Nezahualcoyotl played a crucial technical role.

The aqueduct was a major achievement because Lake Texcoco was largely brackish, making it unsuitable as the city’s main source of drinking water. The system used paired channels or pipes so that one route could continue carrying water while the other was cleaned or repaired. The route extended for several kilometers across the lake environment.

The wording “first aqueduct” can be simplified in popular histories: earlier waterworks and construction attempts may be dated differently in surviving chronicles. Later rulers, especially Ahuítzotl, built or commissioned additional water systems. Nevertheless, among the listed Aztec emperors, Moctezuma I is the standard answer for the original Chapultepec supply.