In California, the 811 color codes are the standardized paint, chalk, and flag colors that utility locators use to show what’s buried under your dig site. The state requires operators to follow the American Public Works Association (APWA) uniform color code, so a yellow line always means the same thing whether you’re in Sacramento or San Diego. Each color identifies one category of underground facility, and two of the colors (white and pink) are placed by people other than the utility company.
The Color Code
California operators field-mark their buried installations using the APWA uniform colors. Here is what each one identifies:
- Red — Electric power lines, cables, and conduit
- Yellow — Gas, oil, steam, or other petroleum and gaseous materials
- Orange — Communication, alarm, or signal lines
- Blue — Potable water
- Green — Sewer and drain lines
- Purple — Reclaimed water, irrigation, and slurry lines
- White — Proposed excavation area, placed by the excavator
- Pink — Temporary survey markings
Who Places Which Marks
Six of the eight colors are placed by the utility operator after you contact 811. Red, yellow, orange, blue, green, and purple all come from a locator sent by the company that owns the line. When you see those on the ground, someone has already been out to your site.
White is different. White marks are yours to place. Before you contact the regional notification center, you outline your proposed dig area in white paint or with white flags. This step, called delineation, tells the locators exactly where to focus. If you skip delineation, an operator can decline to mark anything until you’ve done it.2California Legislative Information. California Code Government Code 4216.2
Pink is also not a utility color. Pink marks come from surveyors and have nothing to do with buried facilities. Seeing pink on a site tells you a surveyor was there, not that anything is or isn’t underneath.
Overlapping Colors in One Area
Gas, electric, and water lines often share the same easement, so a cluster of different-colored marks in one spot usually means multiple utilities running parallel. That’s the situation where the tolerance zone rules matter most, because you can be within striking distance of more than one line at once.
The Tolerance Zone Around Every Mark
Once the marks are down, California law defines a “tolerance zone” of 24 inches on each side of every operator’s field marking.3California Legislative Information. California Code GOV – Government Code A yellow paint line marking a gas pipe creates a two-foot buffer in each direction from that line, and the same goes for every other color.
Inside the tolerance zone, you must determine the exact location of the buried utility using hand tools before running any power-driven excavation or boring equipment. No backhoes, no trenchers, no augers until you’ve physically confirmed where the line sits.4California Legislative Information. California Code Government Code 4216.4
There is one alternative to hand tools: a vacuum excavation device. You can use one inside the tolerance zone, but only if you told the regional notification center when you got your ticket that you intended to, and the operator agreed. If the operator didn’t agree, they’ll note that in their electronic positive response, and you’re back to hand tools.4California Legislative Information. California Code Government Code 4216.4
Treat every marked line as active. Even if you believe a line is abandoned or inactive, the law requires the same care you’d use around a live utility.4California Legislative Information. California Code Government Code 4216.4
When Hand Digging Doesn’t Find the Line
Sometimes you hand-excavate inside the tolerance zone and still can’t locate the installation. When that happens, you can ask the operator for additional information, and the operator must provide whatever relevant records they have within one working day. You can also contact the notification center, which will give you the operator’s phone number so you can coordinate directly.4California Legislative Information. California Code Government Code 4216.4
If You Hit Something
If you discover or cause damage to a gas or hazardous liquid pipeline that results in a leak of flammable, toxic, or corrosive material, call 911 immediately. The same applies to damage involving any high-priority subsurface installation, a category that includes high-pressure natural gas pipelines operating above 60 psi, petroleum pipelines, pressurized sewage lines, electrical conductors at 60,000 volts or more, and hazardous materials pipelines.4California Legislative Information. California Code Government Code 4216.4
How to Get the Marks in the First Place
California has two regional notification centers, split geographically. Northern California is served by USA North 811, and Southern California is served by DigAlert. You can reach either one by dialing 811 or by submitting an online ticket request through their websites. Neither center can charge you a fee for submitting or renewing a ticket.5California Legislative Information. California Code Government Code 4216.1
The sequence is: delineate your dig area in white, contact 811, wait for every operator listed on your ticket to respond, and then look at the marks. Notify at least two working days before you plan to dig. The day you call does not count toward those two days, and you cannot notify more than 14 calendar days in advance. Call on a Monday and your earliest legal start is Wednesday, assuming every operator has responded by then.2California Legislative Information. California Code Government Code 4216.2
Tickets are valid for 28 calendar days from the date of issuance, not from the day you start digging. If your project runs longer or gets delayed by permitting or weather, renew the ticket before it expires. The two-working-day notice does not apply in emergencies, though the statute does not spell out the specific criteria that qualify a situation as one.2California Legislative Information. California Code Government Code 4216.2
What the Operator Must Do
When an operator receives your notification, they must do one of three things before your legal excavation start date: locate and field-mark their installations within the delineated area, provide location information to the extent their records allow, or confirm they have no facilities in your dig zone. Only qualified persons can perform utility locating, and all field marks must conform to the APWA colors above.6California Legislative Information. California Code Government Code 4216.3
A “no facilities” response is itself an answer. If an operator on your ticket confirms nothing is buried in the zone, that color simply won’t appear on the ground, and that’s expected.
What the Colors Won’t Show You
The 811 system covers utilities in the public right-of-way and the connections that run from the main line onto your property. Lines that run entirely on private property, such as a gas line from your meter to a pool heater or irrigation pipes crossing your yard, are generally not covered by the regional notification centers. For those, hiring a private utility locator is often the only way to get them marked. Hourly rates for private locating typically range from $95 to $175 depending on site complexity and the number of utilities involved. Worth considering before you dig in areas where you know private lines exist but 811 won’t touch them.