APWA Utility Color Codes

	White = Proposed Excavation
	Pink = Temporary Survey Markings
	Red = Electric Power Lines, Cables, Conduit and Lighting Cables
	Yellow = Gas, Oil, Steam, Petroleum or Gaseous Materials
	Orange = Communication, Alarm or Signal Lines, Cables or Conduit
	Blue = Potable Water
	Purple = Reclaimed Water, Irrigation and Slurry Lines
	Green = Sewer and Drain Lines

Why are these colors used?
Often, you will see these colors used to identify utility lines in cities and on a university campus. Sometimes city or campus utility departments will paint the tops (such as manhole lids, or sewer drop-inlet tops) of their utilities these colors before an aerial survey is flown so that the people creating the maps can identify the type of utility. If you see utilities being painted in your area, there's a good chance an aerial survey is going to be flown soon. Or sometimes utility departments are just taking inventory of their assets and are painting to identify their utility infrastructure, or possibly to diagnose a problem and they need to identify multiple utility types in an given area.

The utility departments that mark their utilities usually use inverted spray paint, also known as "upside down paint". EngineerSupply sells inverted spray paint by the case.
 

We sell Inverted Utility Marking Paint here