Which map shows wastewater lines, flow direction, and manholes?

• A. Collection System Map
• B. Process Diagram
• C. Site Plan
• D. As-Built Drawing

Answer: (A)

The collection system map is designed to show the sewer network itself—where wastewater lines run, where the flow goes, and the locations of manholes. This type of map highlights the layout of the sewer mains and laterals, includes flow direction arrows to indicate gravity or pressure-driven movement, and marks manhole positions for access and maintenance. It’s the go-to reference for understanding how wastewater travels through the system and where to perform inspections, repairs, or upsizing.

A process diagram focuses on the steps inside a treatment process, not the field layout of sewer lines. A site plan covers the overall site layout and may show some utilities, but it isn’t dedicated to the wastewater collection network with flow directions and manholes. An as-built drawing records the exact installed condition, which can include utilities, but the collection system map is the specific document that maps the entire wastewater network with flow details and manhole locations.