This SU cuts through the opus reticulatum wall (SU 6086) under the wall plug SU 6088 between rooms G-1 and G-7. It appears to drain down toward the road. It is a later feature than the opus reticulatum wall, which it cuts, and appears to have been made after the floor level of G-1 had already been raised significantly. The drain would be below the later floor prep layers SU 6122 and 6121. One of the stones in SU 6167 appears to have been deliberately cut for the purpose of accommodating this drain after the floor level had been raised in subsequent occupation periods.