Which is the term for the middle-size water main in a municipal water distribution system?

• A. Intermediate main
• B. Distributor
• C. Secondary feeder
• D. Trunk line

Answer: (C)

In a municipal water distribution system, mains are classified by size and role from large to small. The largest are trunk lines that carry water long distances from treatment facilities. From there, primary feeders extend the flow into districts, and the lines that sit between these two—large enough to carry substantial flow but not the largest—are secondary feeders. They bridge the gap between the big feeders and the smaller distributor mains that deliver water to streets and homes. That middle position is why the term is secondary feeder. Distributor mains are typically smaller and serve more localized areas, while trunk lines are the biggest.