Discoveries from the current season of excavations at Ramat Rahel are featured in this Jerusalem Post article. The most interesting paragraphs are these:
A highly sophisticated ancient water system dating back to the end of the Kingdom of Judah in the Seventh Century BCE….
The water system, cut deep into the rock foundation, includes large underground water reservoirs, five open pools, small canals that transported water between the pools and three underground canals. The system continued to be functional, although with some alterations, during the Persian Era, the return to Zion after the destruction of the First Temple, the Fifth and Fourth Centuries BCE and through the Hellenistic Era in the Third Century BCE.
Along with 18 Jewish ritual baths from the Hellenistic Period, the archeologists uncovered a bathhouse and villa, and a large Byzantine village with a church, monastery, rooms and halls.
I suspect that the journalist got the date of the ritual baths mixed up; they are almost always from the late Hasmonean or Herodian period. About a dozen were known at the site before the present excavations, dated to the Herodian period. For more about previous excavations at the site, see the current issue of Biblical Archaeology Review for an article by Gabriel Barkay.