APWA Uniform Color Code for Marking Underground Facilities
Underground facilities shall be marked in accordance with the following designated color code:
White: Pre-marking of the outer limits of the proposed excavation or marking the centerline and width of proposed lineal installations of buried facilities.
Pink: Temporary survey markings.
Red: Electric power lines, cables or conduit, and lighting cables.
Yellow: Gas, oil, steam, petroleum, or gaseous materials.
Orange: Communication, alarm or signal lines, cables or conduits, and fiber.
Blue: Potable water.
Purple: Slurry, irrigation and reclaimed water.
Green: Sewers, drainage facilities or other drain lines.