Bidaa Bint Saud (Arabic: بِدَع بِنْت سُعُوْد, romanized: Bidaʿ Bint Suʿūd) is an archaeological site in Eastern Region of the Emirate of Abu Dhabi, the U.A.E., notable for its Hafit Period tombs, Iron Age irrigation systems and rare remains of an Iron Age building thought to have been a distribution centre for water from two aflaj (systems of underground and surface waterways).

[1][5] The dating of aflaj in Bidaa bint Saud, Al Ain and Buraimi, both of which are in the historical region of Tawam,[6] has been placed several centuries prior to the Achaemenid Empire, which had previously been credited with the innovation.

Despite having been plundered in the past, excavations from these Iron Age tombs yielded a number of artefacts, including pottery and stone vessels, dagger blades, bronze arrowheads, and beads.

[1] It is thought Bidaa Bint Saud became an important site during the Iron Age, both as a caravan stop and as a settled community of farmers that used the falaj irrigation system.

While the building's precise purpose remains unclear, archaeologists think it was likely a distribution point for the water from the falaj systems[10] and it has been dubbed Bait Al-Falaj (Arabic: بَيْت ٱلْفَلَج, lit.