Smith's Bible Dictionary
Enrogel
(
fount of the fuller), a spring which formed one of the landmarks on the boundary line between Judah, (
Joshua 15:7) and Benjamin. (
Joshua 18:16) It may be identified with the present "Fountain of the Virgin,"
Ain Umm ed-Daraj , the perennial source from which the pool of Siloam is supplied.
ATS Bible Dictionary
Enrogel
Fuller's fountain, so named because here the fullers were wont to cleanse their cloths by treading them with their feet. This is believed to be the "well of Nehemiah," now called Bir Eyub, Job's well. It is in the valley of the Kidron, just below its junction with the valley of the son of Hinnom, on the southeast corner of Jerusalem,
Joshua 15:7; 18:16. It is mentioned in the Bible in connection with the conspiracy of Absalom,
2 Samuel 17:17, and afterwards with that of Adonijah,
1 Kings 1:9. This well is situated in what is now the prettiest and most fertile spot around Jerusalem. It is one hundred and twenty-five feet deep; is walled up with large squared stones, which on one side rise form an arch, and is apparently of great antiquity.
So as we can see there are different opinions as to where this water source came from in that ancient time...