Hirschfeld et al. (1997:479) concluded that the bathing complex’s occupation came to an end with the earthquake of 749 C.E.. They described the destruction as "almost total" and noted that "the finds dating this destruction are unequivocal—beneath the huge piles of debris consisting of the upper parts of the walls and the ceilings were late finds from the first half of the eighth century C.E." Yizhar Hirschfeld in Stern et al. (1993 v.2:566) further observed that "the fallen debris was eventually covered with earth, and the building was abandoned."

Although a mid-8th-century terminus post quem is well established through coins and associated finds, the terminus ante quem is less certain. The late 10th-century Muslim geographer al‑Maqdisi referred to the baths in the past tense (Yizhar Hirschfeld in Stern et al., 1993 v.2:566), implying that they were already out of use by his time. Supporting this, Hirschfeld et al. (1997:158) found and identified 33 potsherds from the Abbasid–Fatimid period in a portion of the complex that had been leveled after the Phase III seismic destruction.

Hirschfeld et al. (1997:297) also observed that north–south motion caused the principal damage to Hammat Gader in 749, a conclusion inferred from the spatial distribution of debris associated with the partially collapsed columned portal in Area C.

Magness (2010:153–161) re-dated Phase III at Hammat Gader to the Abbasid–Fatimid period rather than the Umayyad period. Her reassessment was based on coins and pottery, including 9th–10th-century buff wares and glazed wares found beneath Phase III structural collapse. This redating would seem to preclude seismic damage from one of the earthquakes in the 749 CE Sabbatical Year sequence, suggesting that if that earthquake affected Hammat Gader, it did so during Phase II or that the evidence for its impact was later obscured by rebuilding.

In Magness (2010)’s interpretation, the bathing complex at Hammat Gader remained in use through the Abbasid–Fatimid periods rather than becoming a ruin, as proposed by Hirschfeld et al. (1997). Magness (2010) further suggested that the final destruction of the complex may have resulted from the 11th-century Palestine Quakes of 1033/4 CE.

However, her Phase III redating is complicated by two pieces of evidence. al-Maqdisi referred to the baths at Hammat Gader in the past tense near the end of the 10th century CE, and the site lay close enough to the epicentral region of the Holy Desert Quake within the 749 CE Sabbatical Year sequence that it must have suffered at least some—likely significant—damage.