What Do the 811 Paint Colors Mean?

The 8 APWA Utility Colors

Red markings indicate electric infrastructure — the most dangerous lines in your yard. High-voltage distribution lines typically run 24–48 inches deep, but secondary service lines (from a transformer to your meter) can be shallower. Never use power equipment within 18–24 inches of red markings. Hand dig through the entire tolerance zone. A struck electric line can cause electrocution, arc flash, and fires. It also cuts power to your neighborhood and triggers costly utility repairs that you may be liable for.

Yellow is the most feared color on a dig site. Natural gas lines run at pressure and a puncture creates an immediate explosion and fire risk. Most residential gas service lines run 18–24 inches deep, but older installations (pre-1970s) may be shallower. If you see yellow marks, treat them with the same respect as red. Hand dig the full tolerance zone. Do not use impact tools, rotary equipment, or mechanical augers near yellow marks.

If you accidentally nick or damage a gas line — even if you don't immediately smell gas — stop all work, evacuate the area, and call 911 and your gas utility immediately. Do not use any electrical switches, phones (near the leak), or open flames.

Orange marks communication infrastructure — phone, cable, and fiber optic lines. While cutting these lines doesn't create a physical danger to you, the consequences are significant: cutting a fiber optic trunk line can knock out internet service for thousands of customers, and you can be held liable for emergency restoration costs that routinely exceed $10,000–$50,000. Telecom companies take these damage claims seriously and pursue them aggressively.

Cable and phone lines are also among the shallowest utility-owned lines. Old telephone drops can be as shallow as 4–6 inches in some residential areas.

Blue marks water lines. Municipal water mains typically run 3–5 feet deep (below frost line), but residential service lines — the pipe from the main to your house — can be shallower on the property-side portion. Hitting a water main causes flooding, soil erosion, and costly emergency repairs. Water utilities typically bill the responsible party for emergency repair costs. A main break can also trigger a boil-water advisory for your neighborhood.

Green marks sewer and storm drain lines. These are gravity-flow systems, so they run at varying depths — shallow near the street, deeper as they proceed to treatment. Residential sewer laterals (from your house to the main) are typically private and NOT covered by 811, but the main running under the street is. Damaging a sewer main means raw sewage exposure, environmental liability, and very expensive emergency repairs.

White is unique: it's you marking where you intend to dig, not a utility locator marking what's underground. When you submit an 811 ticket, best practice is to pre-mark your excavation area in white paint, stakes, or chalk so incoming locators know exactly where to look. Some states require this for larger projects. On a fence-post job, this might mean a few white stakes at your post locations. On a larger project, it's a white outline of the entire dig area.

Pink is a surveying color, not a utility locate color. You may see pink flags or paint after a property survey, when a foundation is being laid out, or when a contractor is staking out a project. Pink markings do not indicate underground infrastructure — they're reference points for above-grade work. They fade or are removed once the survey work is complete.

Purple marks reclaimed (recycled) water lines. These carry treated wastewater repurposed for landscape irrigation, industrial cooling, and similar uses. They're common in drought-prone areas like Arizona, California, and Florida. While not drinking water, reclaimed water systems run at pressure and cutting them causes flooding and contamination concerns. Purple lines are often in commercial and HOA-managed areas but are increasingly found in newer residential developments.

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Quick Reference: All 8 Colors at a Glance

What the Flags and Stakes Mean

Locators use both spray paint and small plastic flags on wire stakes to mark lines. The flags are color-coded the same way as the paint. Flags are common in turf areas where paint won't show well, or when a locator wants to mark a line path with more precision than paint alone allows.

A line of flags in a single color traces the path of that utility. The flags are typically placed every 3–10 feet along the line's route. Do not remove the flags before your work is complete — they're your reference markers for where to hand-dig.

Multiple Colors in the Same Area

It's common to have overlapping markings, especially near utility corridors. When you see red, yellow, and orange markings all within a few feet of each other, that means electric, gas, and telecom all run through that zone. This is a utility corridor and requires extra caution. Hand-dig slowly, expose each line before digging deeper, and never assume you've found everything just because you've found one line.

How Long Do the Marks Last?

Paint marks fade over time — typically 3–6 weeks depending on weather, foot traffic, and lawn mowing. Flags can be knocked over by wind, mowers, or foot traffic. Most states allow you to dig for a set period after your ticket is processed (usually the same as the response window). If your project extends beyond that window, you need to re-notify — and you may need to have the lines re-marked if the originals have faded. See the Re-Notify Rules by State guide for your state's specific window.

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