In the United States, the American Public Works Association (APWA) has established Uniform Color Codes for temporary marking of underground utilities. Onsite technicians apply color codes using paint, chalk, stakes, or flags to indicate the locations and route of various underground utility lines. This standardized color coding system helps contractors, excavators, utility companies, municipalities – or anyone else working on or near underground infrastructure – facilities avoid accidents and damage to water, electricity, or internet supply.
The owners of public lines are responsible for marking the location of underground utilities near a job site, in accordance with the color coding standard:
Red Electric power lines, cables, conduit, and lighting cables
Orange Telecommunication, alarm or signal lines, cables, or conduit
Yellow Natural gas, oil, steam, petroleum, or other gaseous or flammable material
Green Sewers and drain lines
Blue Drinking water
Purple Reclaimed water, irrigation, and slurry lines
Pink Temporary survey markings, unknown/unidentified facilities
White Proposed excavation limits or route