 There is a semicircular cavity below the tubs which must have been intended to catch water which overflowed the tubs.Since there is no drain, this water must have been removed from the room by hand.The tubs are mostly made from a conglomerate cement made of sherds of terracotta and sandstone rubble, although a few of the baths furthest to the west are entirely made in terracotta and are portable (perhaps they belong to the same period as the pavement and, like this, belong to the most ancient period of the bathhouse).