Key Terms The following key terms were used in this lesson: Supply System Supply System Piping systems that convey hot and cold water to supply the needs of plumbing fixtures in the building design. Sanitary System Sanitary System Piping systems that convey the used water away from sanitary fixtures and toward the sewage systems. Riser Riser A vertical pipe. Main Pipe Main Pipe A larger horizontal pipe that supplies water to smaller branch pipes. Branch Pipe Branch Pipe A smaller horizontal pipe that conveys water from the main pipe to an endpoint fixture. Tweet Continue Reading