Which term refers to vertical piping used for multiple purposes beyond water supply?

• A. Main
• B. Branch
• C. Riser
• D. Stack

Answer: (C)

A riser is the vertical piping that serves more than one floor and can carry more than just water—think of it as the building’s vertical spine for multiple services. In tall or multi-story buildings, this pipe runs upward through the structure to distribute water to upper levels and can also carry other systems such as fire protection standpipes or other service lines. That broad, multi-floor reach is what distinguishes a riser from the other terms.

The main is the primary supply line bringing water into the building, not a distribution path through multiple floors. A branch is a smaller line that splits off from the main to feed individual fixtures. A stack is the vertical waste and vent piping, not a multi-purpose vertical distribution for services.