Ancient Jerusalem relied on the Gihon Spring, which emerges on the eastern slope below the City of David ridge. Builders protected access to the spring, channelled water to storage pools, and eventually cut Hezekiah’s Tunnel through bedrock to bring water to the Pool of Siloam inside the city. These works belong to different periods and should not be treated as one project.
Spring defenses and early channels
Archaeological work near the spring has revealed a fortified water complex dating to the Middle Bronze Age, around the eighteenth century BCE. A channel along the slope carried spring water south toward a pool. The City of David’s archaeological guide describes a channel about 400 metres long and explains that excavations since the 1990s changed earlier readings of Warren’s Shaft: the shaft is a natural karst feature exposed when a tunnel floor was lowered much later, rather than the central feature of the Canaanite water system.
In the nineteenth century, Charles Warren explored the underground features and proposed that inhabitants reached the water through the shaft from within the city’s defenses. Modern excavations have identified additional channels, pools, and phases of construction around the spring. The Israel Antiquities Authority’s report on the spring-house area documents buildings and installations alongside the waterworks, showing that the location served practical and civic purposes over time.
Hezekiah’s Tunnel and the inscription
Hezekiah’s Tunnel runs about 533 metres from the Gihon Spring to the Pool of Siloam. The Jewish Virtual Library associates it with King Hezekiah’s preparations for the Assyrian campaign against Jerusalem in 701 BCE, while archaeological dating discussions caution against assigning a precise year to the tunnel’s construction. The route slopes only slightly and was cut from both ends through the rock.
The Siloam Inscription, discovered inside the tunnel in 1880, describes the final stage of the work: the two teams heard one another through the rock and met while cutting toward each other. Its text gives the tunnel’s length in ancient measurement and records water flowing from the spring to the pool. It is an account of the tunnelling operation, not a narrative of a siege. Read the inscription and translation.
What the waterworks reveal
The systems show how Jerusalem’s inhabitants managed an intermittent spring, secured water access, and adapted infrastructure as the city changed. The spring defenses, channels, and tunnel belong to separate building phases, and interpretations have developed as excavation exposed more of the complex. For the monumental buildings on the ridge and finds from nearby excavations, see City of David excavations and the palace debate.