Pool of Siloam

Overview

The Gihon Spring, Jerusalem's only perennial source, lies in the Kidron Valley on the east side of the City of David. Its water was brought to the south end of the ridge, first through an open or semi-open channel (Channel II) and later through the rock-cut Siloam Tunnel. At the south end a reservoir formed behind a massive dam across the mouth of the Tyropoeon Valley. The name 'Siloam' (Hebrew Shiloah, 'sent') is attached to this whole system and to more than one pool built there over time.

In June 2004, during pipe repair work, Ronny Reich and Eli Shukron exposed stone steps of a large stepped pool south-east of the Byzantine church and pool long pointed out to pilgrims. They identified it as the Pool of Siloam of the late Second Temple period, the pool named in John 9. Most of it lay under an orchard; after 2022 the IAA began exposing more of the site.

In 2025 a radiocarbon study (Regev, Szanton, Vukosavovic, Berko, Shalev, Uziel, Mintz, Regev and Boaretto, PNAS) dated straw and twigs in the mortar of the dam to about 800 BCE, the reign of Jehoash or Amaziah of Judah, and argued that the Gihon Spring tower, Channel II and the reservoir formed one building project. The IAA's own 'Atiqot reports on the dam and pool area show that the dating is not settled: a radiocarbon date on dam plaster came out Persian-Hellenistic, against a stratigraphic date of the 7th century-586 BCE.

What the evidence shows

• Stepped pool exposed June 2004 by Reich and Shukron during water-pipe repair south of the Temple Mount; trapezoidal, corners slightly over 90 degrees, one side c. 225 ft (BAS).
• Dam across the Tyropoeon outlet: vertical and slanting sections, at least 19 m long, 11 m high, 10 m wide (PNAS 2025).
• Dam mortar: 3 uncharred straw samples and 1 charred-twig sample, combined 805-795 BCE (68.3%) / 809-792 BCE (95.4%); passes chi-squared test (T = 7.5, 5% = 7.8) (PNAS 2025).
• Earlier date estimates for the dam by various excavators ranged from the 8th to the 1st century BCE, including one radiocarbon date of the 4th-3rd century BCE (PNAS 2025 summary).
• Plaster from the outer face of the dam wall was radiocarbon-dated to the Persian and Hellenistic periods, which the dating report calls 'difficult to explain' against the stratigraphic date of the 7th century-586 BCE ('Atiqot 101).
• Siloam Tunnel floor plaster: a wood sample 810-780 BCE and a short-lived plant 770-550 BCE (Frumkin et al., as summarized in PNAS 2025).
• A separate plastered pool just east of the Siloam Pool, along the outer dam wall, is dated by pottery and coins to the later 1st century CE, probably the last year of the Great Revolt ('Atiqot 101, Greenhut and Mazor).
• Szanton ('Atiqot 113) identifies the Silwan Pool (the 2004 stepped pool) with the Siloam Pool and Birkat el-Hamra with 'Solomon's Pool' of Josephus, all Early Roman.

Open questions

• When was the reservoir dam built? Regev et al. (PNAS 122/35, 2025) date it to c. 800 BCE from four short-lived plant samples in the mortar, arguing that fresh straw would not have been stored for long before use. E. Boaretto's report on the pool plaster ('Atiqot 101, 2025) got Persian-Hellenistic radiocarbon dates from plaster on the outer dam wall, while the excavators' pottery and stratigraphy pointed to the 7th century-586 BCE. The two may date different parts or repairs of the dam; neither report shows that yet.
• Which pool is 'the' Pool of Siloam of Isaiah, Nehemiah and John? The reservoir behind the c. 800 BCE dam is a candidate for the Iron Age pool (Isa 22:9-11 'lower pool', 'reservoir between the two walls'). The 2004 stepped pool is Early Roman. Szanton ('Atiqot 113, 2024) argues from the excavated plan and the written sources that the Silwan Pool = Siloam Pool (for ritual immersion of pilgrims) and Birkat el-Hamra = Solomon's Pool (an open swimming pool). Y. Elitzur (PEQ 140, 2008) argued the Siloam Pool was itself the swimming pool known as 'Solomon's Pool'. The texts give names; the ground gives several pools.
• Whether an Iron Age pool lies under the 2004 stepped pool is unknown; the later construction would have removed or buried it, and no excavation has yet reported one there.

Since 2024

• 2024-11N. Szanton published the argument that the 2004 Silwan Pool is the Siloam Pool used for ritual immersion and that Birkat el-Hamra is Solomon's Pool. [4]
• 2025-01'Atiqot 101 published a newly excavated 1st-century CE plastered pool beside the Siloam Pool, and a radiocarbon report on dam plaster whose Persian-Hellenistic result conflicts with the 7th century-586 BCE stratigraphy. [2]
• 2025-08PNAS radiocarbon study dated the Siloam dam mortar to 805-795 BCE (68.3%), placing the reservoir in the reign of Jehoash or Amaziah and linking it to the Gihon Spring tower and Channel II as one project. [1]

Sources

1. J. Regev, N. Szanton, F. Vukosavovic, I. Berko, Y. Shalev, J. Uziel, E. Mintz, L. Regev and E. Boaretto, 'Radiocarbon dating of Jerusalem's Siloam Dam links climate data and major waterworks', PNAS 122/35 (2025): e2510396122. DOI 10.1073/pnas.2510396122. link excavation report
2. E. Boaretto, 'Radiocarbon Dating of the Plaster of Siloam Pool in the City of David', 'Atiqot 101 (DOI 10.70967/2948-040x.1967, registered 2025). link excavation report
3. Z. Greenhut and G. Mazor, 'The City of David (Ir David), Siloam Road: A Plastered Pool adjacent to the Siloam Pool', 'Atiqot 101 (DOI 10.70967/2948-040x.1964, registered 2025). link excavation report
4. N. Szanton, 'Ritual Purification and Bathing: The Location and Function of Siloam Pool and Solomon's Pool in Second Temple Period Jerusalem', 'Atiqot 113 (published 2024). DOI 10.70967/2948-040x.1031. link study
5. 'The Siloam Pool: Where Jesus Healed the Blind Man', Bible History Daily, Biblical Archaeology Society (from BAR Issue 200, 2009). link study
6. R. Reich and E. Shukron, 'The Pool of Siloam in Jerusalem of the Late Second Temple Period and Its Surroundings', in Unearthing Jerusalem (Penn State University Press / Eisenbrauns, 2011), pp. 241-256. DOI 10.1515/9781575066592-015. link excavation report
7. Y. Elitzur, 'The Siloam Pool - "Solomon's Pool" - was a Swimming Pool', Palestine Exploration Quarterly 140/1 (2008): 17-25. DOI 10.1179/003103208x269114. link study

Checked against new publications through 2026-09.