Drainage channel made up of six pieces, four of which make up the channeling and two make up a flat roof. The final 18.3 m of this canalization are known, which reach perpendicularly to the other sewer preserved in the museum. His trajectory ran below the pool. Most of this sewer was built in "opus caementicium" except for the last section, the one on display in the museum, which was made with stone blocks cut down to form the channel.

Since the time of Augustus, almost all the newly erected Roman cities built their sewerage network, for the evacuation of wastewater. In Caesaraugusta we can see this great sewer in the Forum Museum, which finally ends in the Ebro, to the east of the Stone Bridge.