What is 811, and what happens when you call?
811 is the free national "call before you dig" service. You report where you plan to dig, member utilities send locators to mark their buried lines with paint and flags, and only then is it legal to dig.
Every state routes 811 to its own one-call center. You give the dig site, the type of work, and when you plan to start. The center notifies every member utility with lines in the area, and each one sends a locator or responds "clear."
The rules that matter
Wait times and ticket life vary by state, but the pattern is the same: a required waiting period before you can dig (commonly 2 to 3 business days), a window the marks are valid for (10 business days in New Jersey, for example), and a tolerance zone around each mark (typically 18 to 24 inches on each side) where you must hand-dig or soft-dig.
What it doesn't cover
811 marks public utility lines. Private lines, like the gas run to a pool heater, an irrigation system, or a well feed, are not marked. If the property has private utilities, a private locate service is a separate call.
Digging without a valid ticket risks lives first and fines second, and a hit line without a ticket is on you. Track ticket numbers and expiration dates on the job, and re-call before marks lapse mid-project.