Q: When utility companies mark underground utility lines at a proposed excavation site, which paint colors correspond with which utilities?
A: Ultimately, the state or local government has final say about color codes, but the Call 811 utility-location service, which is free to use nationwide, follows the APWA uniform color code (ANSI Z535.1) for marking excavation sites and underground facilities in conflict with an excavation. Red indicates electrical power lines or cables. Yellow indicates gas, oil, steam, petroleum or other gaseous materials. Orange indicates communication, alarm or signal lines. Blue indicates potable water. Purple indicates reclaimed water, irrigation and slurry lines. Green indicates sewers and drain lines.