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Glossary

811

What is 811?

811 is the free North American call-before-you-dig phone number that notifies utility owners to mark buried lines before excavation; contacting 811 is a legally required first step before digging, including hydro excavation.

Dialing 811 (or submitting an online locate request) triggers a One Call notification to local utility operators, who then mark the approximate location of buried gas, electric, water, and telecom lines with paint and flags. This service is free and required by law in most jurisdictions before excavation.

After lines are marked, crews commonly daylight or pothole with hydro excavation to precisely confirm depth and position before mechanical digging. 811 marking and vacuum excavation work together to prevent utility strikes. Vac4Rent helps you rent the non-destructive digging equipment used after you call 811.

Guides that cover 811

Related terms

Call Before You DigUtility LocatingPotholingDaylighting

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811: common questions

What is 811?+

811 is the free North American call-before-you-dig phone number that notifies utility owners to mark buried lines before excavation; contacting 811 is a legally required first step before digging, including hydro excavation.

What do the colors of 811 utility marks mean?+

Most US locators follow the American Public Works Association uniform color code. Red marks electric lines, yellow marks gas, oil, or steam, orange marks communications, blue marks potable water, green marks sewer and storm drains, and purple marks reclaimed water or irrigation. Pink is used for temporary survey markings and white outlines the proposed excavation area. Marks show approximate location, so exposing the line is still needed to confirm it.

Does 811 locate private utility lines?+

Generally no. The 811 system notifies member utility operators, who mark the facilities they own, often up to the meter or property line. Private lines, such as service lines to outbuildings, private water or sewer lines, irrigation, and site lighting, are usually the property owner's responsibility and may need a private locating service. Hydro excavation is often used to confirm both public and private lines before digging.

How long do I have to wait after calling 811 before digging?+

The waiting period is set by each state, commonly a few business days, and the start date and ticket lifespan also vary. Before digging, confirm that every notified utility has marked or cleared the area, and renew the ticket if the work runs past its expiration. Within the tolerance zone around marks, many states require hand digging or non-destructive methods such as hydro excavation. Check your state one call center's rules.