The Siloam Aqueduct

In the years that Sennacherib was carrying on wars against Babylon and Elam, Hezekiah fortified his cities, repaired the citadel of Millo at Jerusalem, prepared arrows and shields, ordered that the fountains and brooks in the land be stopped at the first sign of invasion, and with the help of the prophet Isaiah, heartened the people. Once more he concluded an alliance with the Egyptians and the Ethiopians, and waited for Sennacherib to come again.

Hezekiah realized the importance of an adequate water supply in case of siege. Harboring in his heart the thought to resist Sennacherib should he try to continue to reduce Jerusalem and the surrounding towns to vassalage and exploit the people’s resources and the royal treasury, once the appetite of the conquerors was awakened, Hezekiah was prepared to sacrifice the cities outside Jerusalem and was set upon to part with life, but not to open once more the gates of the capital before the ravenous pillager from the banks of the Tigris. He planned to secure water for the inhabitants of Jerusalem and executed the plan.

. . . Hezekiah also stopped the upper watercourse of Gihon and brought it straight down to the west side of the city of David. (II Chronicles 32: 30)

And the rest of the acts of Hezekiah, and all his might, and how he made a pool, and a conduit, and brought water into the city, are they not written in the book of the Chronicles of the kings of Judah? (II Kings 20: 20)

The book of the Chronicles of the Kings of Judah must have been a much more extensive work than the just quoted book of Chronicles.

In the Old City of Jerusalem, inside the walls, in the Christian sector, till today the large stone pool serving as a reservoir is shown; it carries the name Breikhat Hezekiah, or the Reservoir (pool) of Hezekiah. In 1880, south of the Temple area in Jerusalem, in the rock wall of the lower entrance to the tunnel of Hezekiah, an inscription was discovered. It actually occupied the lower part of a prepared stone surface and is therefore judged to be but the last half of the planned (or even executed) inscription. Six lines remain. For the upper part the mason could have planned the date of the execution and the purpose, possibly referring to its value in war time.

The source of water lies lower than the reservoir and it needed to be raised to adequate height by mechanical means—an engineering feat solvable by means whether primitive or more sophisticated. But a real engineering achievement was in digging the conduit simultaneously from two ends, especially considering the substantial distance from the spring to the reservoir and the depth from the surface of the rock to the conduit beneath.

The inscription—in biblical Hebrew—slightly damaged, in its six lines tells:

[.. when] (the tunnel) was driven through. And this was the way in which it was cut through: >_ While [. ..] (were) still [..] axe(s), each man toward his fellow, and while there were still three cubits to be cut through, [there was heard] the voice of a man calling to his fellow, for there was an overlap in the rock on the right [and on the left]. And when the tunnel was driven through, the quarrymen hewed (the rock), each man toward his fellow, axe against axe; and the water flowed from the spring toward the reservoir for 1,200 cubits, and the height of the rock above the head(s) of the quarrymen was 100 cubits.(1)

The two teams of excavators of the channel for the conduit, one working in the rock formation beginning from the end designated for the reservoir, the other standing at a distance of 1,200 cubits at the underground spring, heard each other when they were separated by the last intervening three cubits of rock. Even in modern times, with all the developed surveillance methods, road tunnels running under mountain passes, when dug from two ends with the two teams not bypassing each other, are a cause of celebration—a deviation of even a fraction of a degree would result in a failure.

For supplying Jerusalem with water and for security reasons, Hezekiah, as already quoted, “stopped the upper watercourse of Gihon and brought it straight down to the west side of the city of David."

When the feared moment arrived and “Hezekiah saw that Sennacherib was come, and that he was purposed to fight against Jerusalem,” the governors were summoned to the city.

He took counsel with his princes and his mighty men to stop the water of the fountains which were without the city: and they did help him.

So there were gathered much people together, who stopped all the fountains, and the brook that ran through the midst of the land, saying, Why should the kings of Assyria come, and find much water? (II Chronicles 32: 3-4)

But Sennacherib—Isaiah speaking for him—said: “I have digged and drunk water; and with the sole of my feet I have dried up all the rivers of the besieged places."  (2)


  1. The Siloam Inscription,” transl. by W. F. Albright in James b. Pritchard ed., Ancient Near Eastern Texts Relati ng to the Old Testament (Princeton, 1950), p. 321.

  2. Isaiah 37: 25.