What do the Flags and Markings Mean?
Category:
Public Works
The Common Ground Alliance (CGA) maintains a set of Guidelines for Operator Facility Field Delineation to indicate the infrastructural pathways of buried wires and pipelines. The CGA Best Practices are designed to improve worker safety, protect vital underground infrastructure, and ensure public safety during excavation activities conducted in the vicinity of existing underground facilities.
Facility operators are required to mark all underground utility lines with standard color codes as established by the American Public Works Association (APWA).
APWA Uniform Color Code:
- White - Area of Proposed Excavation
- Orange - Communication, CATV, Fiber
- Red - Electric
- Purple - Reclaimed Water, Irrigation
- Pink - Temporary Survey Markings
- Blue - Water
- Yellow - Gas, Oil, Steam, Propane
- Green - Sewer
Utilities that Require Markings:
- Communications Cables
- Gas Lines
- Electric Lines
- Ethernet and Fiber Optic Cables
- Metal and Concrete Pipes
- Sewer Lines
- Water Pipes
For more information, visit:
Updated 10/16/2025 12:37 PM