SU 8031 served as the wall separating Rooms I-2 and I-3 from I-4, I-8, and I-9. It stretches from the eastern side of the ashlar threshold in Room I4 (su 8019) to the eastern edge of the structure. The lead drain, which appears to be built into the wall, allowed liquid to drain from basin 8029 to the holding tank SU 8047. Thus, 8031 was made from the beginning to be part of the system that operates using Room I-1, the lead drain, and the tub created by 8047 -- perhaps a system for pressing wine or olive oil. The somewhat odd angle created by the intersection of this wall with 8038 to the east may suggest that the two walls were not built in the same phase (see also odd intersection of 8030 and 8077 on the western side).The change in the wall directly over cut 8022 suggests that some sort of partition wall once existed between 8012 and 8031.