APWA colors for underground utility markings

Before excavation, utility locators use paint, flags or stakes to show the approximate route of buried facilities. Color gives the crew a fast clue about what may be underground, while letters or owner information can add detail. The APWA color code is a field reference; a mark does not grant permission to dig through a utility's tolerance zone.

Memorize the facility colors

Orange is communications

Orange marks communications-related facilities such as telephone, cable television, alarm or signal lines, and associated conduit. It does not mean gas or power; those are yellow and red, respectively. A single excavation area may show several colors where different facility types share a corridor.

White and pink describe the work area

White outlines where excavation is proposed, helping locators identify which part of a site must be marked. Pink identifies temporary survey markings. The marks may include abbreviations, company identifiers, dimensions or offset information. They communicate the locator's intended reference, so read the accompanying text as well as the paint color.

Marks do not replace safe-dig procedures

APWA guidance exists to reduce damage and service interruption. The One-Call system must be contacted before excavation under applicable law. If work approaches a marked facility, follow the jurisdiction's tolerance zone and exposure method requirements; powered equipment may be restricted until the line is exposed. Marks can fade or become displaced, and their exact meaning and required waiting period are governed by state one-call rules and project procedure.

Fast recall

• Red: electricity.
• Yellow: gas and hazardous materials.
• Orange: communications.
• Blue: potable water; purple: reclaimed water.
• Green: sewer and drain.
• White: proposed dig; pink: survey.

Use the color code as a warning, not a complete locate

The commonly used APWA uniform color code helps crews identify the general type of underground facility indicated by temporary surface marks. Red is commonly associated with electric power, yellow with gas or petroleum, orange with communications, blue with potable water, green with sewer or drain, and purple with reclaimed water or irrigation. White commonly identifies a proposed excavation area. Colors do not disclose exact depth, ownership, condition, or safe clearance. Use the applicable one-call system and site procedures, and treat marks as approximate indications to be verified.

Plan the locate before excavation begins

The excavator should give notice to the one-call center with a clear work area and sufficient lead time under state law and local rules. Mark proposed excavation limits in white where required or requested. Confirm ticket status for each notified facility owner and do not begin until required responses are complete. An emergency ticket has a defined legal meaning; it is not a shortcut for poor planning. Keep ticket numbers and locate records at the work site and re-notify if a ticket expires, work moves outside the marked area, or conditions make marks unusable.

Know what a tolerance zone changes

State law defines the tolerance zone and precautions when excavation approaches a marked facility. Often, work within that zone requires careful exposure by hand or another approved non-destructive method, but the width and permitted equipment vary. Verify exact location and depth by potholing or another authorized method. Do not assume a painted line is centered over the facility or that a line runs straight between marks. Use spotters and controlled excavation where needed, and support exposed utilities so they are not damaged by movement or loss of bedding.

Respond safely to mismatches and damaged marks

If marks conflict with plans, disappear, or do not match exposed facilities, stop affected work and contact the facility owner or one-call process for clarification. Never move, erase, or cover a locate mark without coordinating. If a line is struck or an odor, leak, arc, or other hazard appears, stop equipment, evacuate as appropriate, keep people away, and contact emergency services and the utility owner under the site response plan. Do not attempt an improvised repair. Even an apparent scrape or coating nick can cause a serious future failure.

Record the locate and protect it through the work

Photograph markings before they fade, record dates and ticket responses, note pothole locations and verified depths, and identify exposed crossings. Refresh marks as required and coordinate with other crews to avoid confusion between different locate batches. Check state-specific rules on positive response, ticket validity, tolerance zones, and damage reporting because they differ. Color recognition is only the beginning: notice, owner response, careful exposure, protection, and incident reporting are separate duties that work together to prevent utility strikes.

Example: markings cross the excavation limits

A crew receives a locate ticket, but orange and yellow marks run through the proposed trench and one facility owner has not responded. The crew should verify positive responses, preserve the ticket, and obtain clarification before excavation in the affected area. Once authorized work starts, expose facilities carefully in the tolerance zone using methods allowed by state law. Confirm depth and alignment at crossings and protect exposed services. A paint color alone does not authorize mechanical excavation directly over a line.

Plan for changing work and expired tickets

If the trench moves, the scope expands, marks are destroyed by paving, or the ticket expires before work is complete, obtain a refreshed locate as required. Share current marks and ticket details with subcontractors and equipment operators at the daily briefing. Keep a spotter where equipment works near exposed utilities and stop if a facility is not where expected. These simple controls prevent the frequent error of treating a locate as permanent for the entire site.

Coordinate with the excavation competent person

The competent person should review the excavation protection plan alongside utility information, soil conditions, water accumulation, and changing work. Locate marks help identify buried services, but they do not replace protective-system inspections or safe access requirements. Before workers enter, verify that exposed utilities are supported, spoil and equipment are kept back as required, and the excavation is inspected after rain or other hazard-increasing events. Brief crews on the location of known lines and the stop-work signal so a locate discrepancy is acted on immediately.

Key takeaway

Remember orange for communications and white for the proposed excavation. Use the full color legend, markings and text together, then follow the one-call notice and local safe-dig rules before work begins.