Reading Locate Marks: The Color Code and Offsets

Intro0:00

Before you dig, the law requires asking the utility owners to locate their lines. But locates only protect you if you read them right. Locate marks use a uniform color code with eight colors, though a state may specify other colors. Six mark types of buried line, and two mark something other than a line.

The Color Code0:18

Respect every color. Here is what each one means. Yellow marks gas, oil, steam, petroleum or gaseous materials. Red marks electric power and lighting lines. Orange marks communication, alarm or signal lines. Blue marks drinking water. Green marks sewers and drain lines. Purple marks reclaimed water, irrigation and slurry lines. Pink marks temporary survey markings. And white marks the proposed excavation: your dig. If your dig site can't be clearly described on the locate ticket, it's a good habit to mark the route or area to be dug in white. Do it on site, or electronically where your 811 center offers it, before or during the locate request.

Offsets1:00

A good habit when you read the marks: remember a mark is not always on top of the line. Where site conditions make it hard to mark the line or keep a mark on it, locators may use offset marks, together with marks over the line when they can. And as digging gets close to where a line is estimated to be, the law requires finding its exact location by safe and acceptable means. If a surface feature used for offsets is changed or moved, it's wise to treat that part of the locate as no longer valid and get it re-marked.

Keep the Marks Good1:32

It's recommended to protect and preserve the marks until they're no longer needed for safe digging. If a mark is removed or can no longer be seen, the recommended step is to stop digging and ask 811 for a re-mark. Best practice: photograph the marks before digging, as a record. A photo never replaces the marks on the ground. Near a pipeline, the law requires calling 811 again as needed, so it's located and marked before you dig.

Recap1:58

To recap. Good habits: if your dig can't be clearly described on the ticket, mark it in white. Remember a mark may be an offset, not on top of the line. Protect the marks; if one is removed or can't be seen, stop digging and ask 811 for a re-mark. In short: yellow is gas, oil, steam and petroleum, red is power, orange is communications, alarm and signal lines, blue is drinking water, green is sewers and drains, purple is reclaimed water, irrigation and slurry. And close to a marked line, find its exact location by safe means before you dig on.