A sewer camera and a sonde tell a contractor exactly where to dig for a repair. They say nothing about what else is buried there, and the gas service, the electric cable, the fibre and the water main are the things that hurt people and cost money when a bucket finds them. The 811 service exists so that anyone about to dig can have the public utilities marked for free before they start, and in every US state the call is required by law before mechanised excavation. This guide covers how it works for a sewer repair and what it does not do.
Quick answer: call 811 or use the state’s online portal at least two to three working days before the dig, with the address, the location on the property and the size of the excavation; outline the dig area in white paint or flags first. Each utility with lines nearby sends a locator to mark them in the standard colours, or responds that it has nothing in the area. Dig by hand within the tolerance zone, usually eighteen inches to two feet, either side of any mark. The service marks public utilities to the meter or the property line only; private lines beyond that, the pool feed, the shed cable, the irrigation, the gas line to the grill, are the owner’s to find. Skipping the call is illegal and leaves the digger liable for everything they hit.
What 811 is
A national number that routes to the one-call centre for the state, which notifies every utility registered in the area of the proposed dig. The utilities then locate and mark their facilities or report that they have none there. The service is free to the caller and paid for by the utilities, who would rather mark than repair.
When to call
Each state sets a notice period, commonly two or three working days excluding the day of the call, and the marks are valid for a limited period, often ten to fourteen days, after which a renewal is needed. Call as soon as the sewer repair is scheduled. An emergency repair for an active sewage backup can be requested as an emergency locate with a shorter response, but the call is still made.
Before the call
Outline the proposed excavation in white paint or white flags so the locators know where to look, and have the sewer’s own green locate already marked inside it. Describe the dig precisely: the address, which side of the house, the distance from a fixed point, and the size. A vague description gets a vague locate. The marking colour code explains white-lining and the colours that will appear.
What arrives
Over the following days, locators from each utility mark their lines in paint and flags: red for electric, yellow for gas, orange for communications, blue for water, and the public sewer in green if the utility marks laterals, which many do not. Utilities with nothing in the area respond through the one-call system. Before digging, check that every utility notified has either marked or cleared; a missing response is a reason to wait and call back.
The tolerance zone
Marks show the approximate centreline, and the law in each state defines a zone either side, often eighteen inches to two feet, within which only hand digging or vacuum excavation is permitted until the facility is exposed. The zone exists because locates are estimates. A sewer repair trench that crosses a marked gas service is dug by hand across the zone, with the gas line exposed and supported before any machine comes near.
What 811 does not mark
Private lines beyond the utility’s meter or the property line: the electric feed from the house to a pool pump, shed or gate, the gas line from the meter to a grill or a pool heater, irrigation, landscape lighting, a private water line to an outbuilding, septic components, and the private sewer lateral itself in most jurisdictions. Finding those is the owner’s or the contractor’s job, by passive sweep, by tracing or by hiring a private locator. Passive locating and tracer wire cover two methods.
The sewer itself
The camera and sonde locate of the lateral is the contractor’s mark, in green, with depth and distance written beside it. It sits inside the white outline and alongside the utilities’ marks, and the excavation is planned around all of them together. Marking a dig and tracing the lateral cover getting the green mark right.
Liability
A contractor who digs without a valid 811 ticket is liable for any damage and faces fines in most states; a homeowner digging their own sewer repair is under the same law. With a valid ticket, a contractor who follows the marks and the tolerance zone and still hits an unmarked or mismarked public line is generally not liable for it. The ticket number is kept with the job file. Liability and insurance covers the contractor’s position.
Emergency repairs
A collapsed lateral with sewage in the basement is an emergency, and one-call centres provide emergency locates with shorter notice, sometimes within hours. The call is still made, the response is still waited for, and the hand-digging rule still applies.
Trenchless work
Lining, pipe bursting and horizontal drilling still involve excavation at access pits and a bursting or drilling path that crosses other utilities. The 811 call covers the pits, and the path is planned around the marks; cross-bores into a sewer by directional drilling are the reason the sewer industry inspects for them. Cross-bore inspection protocols and pipe bursting cover both.
Keeping the record
The ticket number, the date, the utilities’ responses and photographs of the marks go in the job file with the camera footage and the locate. If a line is hit, this is the record that decides who pays.
Common questions
Do I have to call 811 for a sewer repair in my own yard?
Yes, in every US state, before any mechanised digging. The call is free and the marks are required.
Does 811 mark my sewer lateral?
Usually not. Most utilities mark only the public main. The lateral is located with a camera sonde and marked in green by whoever is doing the repair.
How long are 811 marks valid?
It varies by state, commonly ten to fourteen days, after which the ticket must be renewed before digging continues.
Related guides
See sewer repair permits and inspections, measuring lateral length, and testing a 512 Hz sonde above ground.