Sewer Line Locating: Find the Route and Understand the Limits
Sewer locating helps relate an accessible buried pipe or camera finding to the ground surface. A compatible sonde transmits a signal that a receiver can detect above ground. The result can guide assessment and repair planning, but it is not a legal survey or a complete clearance to excavate.
What a locating visit can establish
A transmitting camera head or other suitable sonde can be positioned at selected points in a pipe. The operator detects the signal at the surface to estimate location and, where readings are reliable, depth. Several points can help describe a route or relate a visible defect to a repair area.
The equipment needs access to the relevant reach. A severe blockage, tight bend or incompatible access can prevent the sonde reaching the target. Report buried cleanouts and previous footage before booking so the contractor can assess whether the planned task is feasible.
Why the mark is an estimate
Signal interference, nearby metal, depth, transmitter orientation and site conditions can affect interpretation. A receiver reading should be checked rather than treated as an exact coordinate. Ask the operator to state uncertainty and distinguish a confident mark from an approximate route.
Cable travel does not equal a straight surface distance. A camera may traverse bends or hold slack, so a displayed distance should be tied to a known starting point. Inspection footage and locating notes should use the same reference.
A sewer location is not a utility clearance
Locating the private sewer does not identify all gas, electric, water or communication infrastructure along the proposed excavation. Before ground disturbance, obtain and review the required utility locates through Ontario Dig Authority and identify any privately owned services needing separate attention.
Do not infer a safe digging depth from a sonde estimate alone. The excavation contractor must plan safe exposure and respect locate instructions. A mark showing the camera head also does not establish the legal property line or permission to work within a road allowance.
Defect location and municipal responsibility
When a municipality may be responsible for a damaged section, ask what location evidence and footage it requires. A sketch should identify fixed surface references and the inspected direction. The municipality, rather than a generic property-line assumption, determines how its procedure applies.
For a repair quote, request the defect’s location, access constraints and depth assumptions together. A marked spot without the underlying footage can be difficult for another contractor to interpret.
What to request in the handover
Confirm whether the fee includes camera access, tracing multiple points, depth estimates, photographs and a route sketch. Note the date, reference point, equipment limitations and any unreachable length. Ask how temporary surface marks will be preserved in a durable record.
Tell the provider whether the purpose is finding a cleanout, planning a spot repair or documenting a suspected public-side problem. These are different tasks and may need different access. Confirm compatible equipment and current availability before relying on locating as the next project step.
Sources and local guidance
Source check: October 23, 2026. Municipal procedures and equipment instructions can change; use the linked authority for current details.
Explain what needs to be located
Share existing footage and say whether you need a route, defect position or access point identified. Confirm the deliverables and limitations.