811 Call Before You Dig: State Rules and Tolerance Zones

811 is the starting point for excavation planning

Calling 811 or submitting a locate request connects an excavator with the participating utility operators in the work area. The request gives those operators a chance to mark or otherwise respond about their underground facilities before digging begins. The exact notice period, ticket rules, marking practices, tolerance-zone requirements, and remedies come from the state and the current one-call process.

This is not just a contractor step. Homeowners, builders, landscapers, demolition crews, utility subcontractors, and anyone planning excavation should check the applicable state process. “It is my property” and “the trench is shallow” do not reliably identify where buried facilities are or remove the need to verify the current rule.

Use 811 as a damage-prevention process, not as a promise that every line on private property will be found. Public utility participation, private lines, abandoned facilities, inaccurate records, marks that fade, and changes to the work area all require additional attention.

The information to include in a locate request

A useful ticket describes the excavation area, the address or site location, the start date, the type of work, the equipment or methods involved, and how the excavator will receive responses. A long or complicated project may need multiple tickets, updates, remark requests, or direct coordination with the notification center and utility owners.

Mark the proposed excavation area clearly when the state or ticket process requires it, and use white paint, flags, or stakes when white-lining helps the locator identify the actual work limits. White-lining is especially useful when a property is large but excavation will occur in only a small portion. Do not mark a vague area and then assume the ticket covers a later alignment.

Keep the ticket number, request date, work description, responses, maps, photographs, and any written utility instructions in the project file. The person performing the excavation should be able to match the marked site to the ticket before equipment starts.

Read the utility marking colors—but do not treat them as exact coordinates

The uniform marking colors used by the damage-prevention industry generally identify the utility type: red for electric, yellow for gas or petroleum, orange for communications, blue for potable water, green for sewer, and purple for reclaimed water or irrigation. White is commonly used to show proposed excavation limits, while pink is used for temporary survey markings. Confirm the current color legend supplied by the applicable one-call center.

Paint and flags show an approximate route, not a guaranteed depth or exact edge. Erosion, landscaping, previous construction, settlement, inaccurate records, and changes in grade can move the apparent relationship between a mark and the facility. A pipeline marker, map, or old as-built drawing is not a substitute for the current locate response.

If the work area changes, marks are destroyed, or a facility response is unclear, stop in the affected area and request the appropriate update, remark, no-response, or clarification process. Do not extend the excavation simply because another portion of the property was marked.

Tolerance zones are state-specific

A tolerance zone is the area around a marked underground facility where extra care is required. The width and the required excavation methods vary by state, utility type, and sometimes the applicable statute or rule. There is no single nationwide 18-inch or 24-inch rule that can safely be copied onto every project.

Texas provides a useful example of why precision matters. Texas811 explains that Texas law does not specify one general tolerance-zone margin for every marked utility, while Texas pipeline rules define a tolerance zone using half the nominal pipeline diameter plus at least 18 inches on each side. Texas811 also describes hand digging, soft digging, vacuum methods, and other reasonable-care practices for excavation near a pipeline.

Florida provides a different example. Sunshine 811 describes a 24-inch tolerance zone from the outer edge of an underground facility and says increased caution, including hand digging, potholing, soft digging, or vacuum excavation, is required within that zone. Use the state’s current law and one-call guidance for the actual work location; never infer a rule from a neighboring state.

What to do inside the tolerance zone

The safe method depends on the state rule, facility owner, soil, depth, exposure, and work plan. Common controls include exposing the facility carefully by hand or vacuum, using non-destructive methods, maintaining a visible reference, supporting the facility if required, and keeping mechanical equipment under the supervision or restrictions specified by the applicable rule.

A tolerance zone is not permission to dig carelessly until a bucket touches a line. The goal is to identify the facility’s actual horizontal and vertical position while controlling force, vibration, spoil placement, and movement around it. The utility owner or project plan may impose additional requirements beyond the state minimum.

Coordinate crossings and parallel work before excavation. Record the facility location, exposure method, depth, support, protection, and restoration plan. If a line is not where the marks indicate, stop and resolve the discrepancy before continuing.

Public locates do not cover every private line

One-call centers notify participating utility operators, but private facilities may not be included in the public locate. Lines from a meter to a detached building, private lighting, irrigation, septic systems, private water or sewer, farm utilities, and owner-installed communications may require a private utility locator or direct owner coordination.

Ask who owns each facility and what the ticket covers. A “clear” response can mean that a utility operator has no conflict in the described area; it does not mean the property contains no buried facilities. Confirm the ticket’s affected utilities and compare each response with the work limits.

For demolition, excavation, and new service work, include private locating and utility shutoff in the scope. A locate ticket is not a disconnection, cap, abandonment, permit, or authorization to start.

When can work begin?

Do not start simply because the request was submitted or because paint is visible. Confirm that the required notice period has passed, every affected operator has responded or the applicable no-response process has been followed, the markings are visible, the ticket still covers the exact work area and method, and the project has satisfied any additional state or utility-owner conditions.

Ticket life and update rules vary. Texas811 explains a Texas 14-day rule for a properly timed notice and says the excavator is responsible for updating or remarking when work is delayed or marks are no longer usable. Sunshine 811 publishes different Florida requirements, including a two-full-business-day notification process and its own mark and ticket guidance. These are examples, not universal terms.

Before the first cut, hold a short field check: match the address and limits, review the ticket, identify all responses, walk the marks, confirm private utilities, review the excavation method and tolerance-zone controls, and document who is authorized to proceed.

If a utility is missing, damaged, or exposed

Stop work in the affected area when a facility is exposed unexpectedly, a mark is unclear, a response is missing, or the facility does not match the ticket. Protect people from electrical, gas, pressure, flooding, traffic, and structural hazards, then contact the notification center and the utility owner using the applicable emergency process.

If a gas line is hit or damaged, move people away from the hazard and call 911 in addition to reporting the damage through the applicable one-call process. Do not cover, move, repair, or backfill a damaged facility unless the owner or emergency authority directs the response.

Document the location, time, ticket, condition, photos from a safe position, equipment status, notifications, and instructions received. The incident record supports a controlled response and helps prevent the same location from being treated as cleared without resolution.

Use the permits and 811 workstation

The permits and 811 workstation helps organize the state, city, project type, utility status, notice timing, and jurisdiction questions that should be answered before excavation. Use it to create a preflight checklist and identify where the actual one-call center, utility owner, or authority having jurisdiction must be contacted.

The workstation does not issue a ticket, locate a private line, determine legal liability, confirm a utility response, or replace the current state law. Save the result with the ticket number and project notes, then verify the live requirements at the work location before digging.