Locating and sonde work

Using a transmitter in the line and a receiver above ground to trace its route.

What this page cannot establish

Locating and sonde work cannot establish exact pipe position or depth
Locating and sonde work cannot establish the condition of the pipe
Locating and sonde work cannot establish the location of other utilities

What it is for

To mark on the surface where the line appears to run, and sometimes at approximately what depth.

When a professional may raise it

These are circumstances, not rules. No method is appropriate everywhere, and a professional declining to use one is not necessarily cutting a corner.

when excavation is being considered and the route matters
when a camera observation needs to be tied to a surface position
when access, landscaping, or hardscape would be affected by the route

What to ask for afterwards

A method performed without a record produces very little you can carry into the next conversation.

photographs of the marks with the date
a note of depth readings if taken
a note of the reference point distances are measured from

Practical constraints

surface conditions and other buried services can affect readings
marks weather away
depth readings are approximate

Questions worth asking

How accurate is this locate, and what affects that?
Was depth recorded as well as route?
Does this route cross anything that would need restoring?

What would change the answer

photographs of the marks with the date
a note of depth readings if taken
a note of the reference point distances are measured from

What to do next

Route and depth are what determine which surfaces get disturbed, which is the most under-specified part of most proposals.

Understand how position affects excavation scope

If your situation is different

You are trying to work out whose side a defect is on: When responsibility is disputed

Footage markers
A camera distance and a surface position are different measurements.
Restoration
What the route crosses determines what has to be put back.