Inspections and evidence
An inspection is how anything specific about a buried line becomes known. It is also where most of the confusion enters: a camera recording is a record of what a lens saw from where it was, and that is a narrower thing than "the condition of the line".
These pages cover what each method attempts, what to insist on receiving, and — on every page — what the method cannot establish no matter how well it is performed.
What this page cannot establish
- no inspection method establishes ownership or legal responsibility
- no inspection establishes the condition of a section it did not reach
- SewerOwner cannot interpret your footage or confirm any inspector’s findings
- nothing here replaces a licensed professional’s assessment
Inspection and evidence methods
- Camera inspectionUnderstand what sewer camera inspection would tell me, and what it would not.
- Cleaning firstUnderstand what cleaning before inspection would tell me, and what it would not.
- LocatingUnderstand what locating and sonde work would tell me, and what it would not.
- Footage markersUnderstand what measuring approximate defect position would tell me, and what it would not.
- Dye testingUnderstand what dye testing would tell me, and what it would not.
- Smoke testingUnderstand what smoke testing would tell me, and what it would not.
- Pressure testingUnderstand what pressure or leakage testing would tell me, and what it would not.
- Excavation confirmationUnderstand what excavation confirmation would tell me, and what it would not.
- Municipal recordsUnderstand what municipal record review would tell me, and what it would not.
- Camera limitsWork out how much weight the footage I was shown can actually carry.
- Written reportsWork out which parts of this report are observations and which are recommendations.
- Evidence provenanceKeep straight what I know, what I was told, and what has actually been established.
All methods at a glance
Not every method applies to every situation. A professional discussing one and not another is making a judgement about your property, and it is reasonable to ask what that judgement rests on.
Visual site review
A professional looking at the property, fixtures, and accessible plumbing.
To establish what is visible without equipment: which fixtures behave how, where access points are, what the site allows, and what is worth investigating further.
Cannot establish: the condition of buried pipe; the cause of any symptom; the route or depth of the line.
Sewer camera inspection
A camera pushed through the line to record what it passes.
To record what is visible inside the line along the path the camera travels from a given access point.
Cannot establish: the condition of sections the camera did not reach; ownership or legal responsibility; structural capacity; code compliance; that a specific repair method is appropriate; the significance of a visible feature without professional context.
Cleaning before inspection
Clearing the line first so a camera can see more than debris.
To remove material that would otherwise obscure the lens, so that an inspection records the line rather than its contents.
Cannot establish: what the line looked like before it was cleaned; that removed material explains the symptom; that the condition will not return.
Locating and sonde work
Using a transmitter in the line and a receiver above ground to trace its route.
To mark on the surface where the line appears to run, and sometimes at approximately what depth.
Cannot establish: exact pipe position or depth; the condition of the pipe; the location of other utilities.
Measuring approximate defect position
Tying an observation inside the line to a distance and, sometimes, a surface point.
To establish where along the line an observation sits, so that work, second opinions, and responsibility questions can refer to the same place.
Cannot establish: a precise property coordinate; which side of a responsibility boundary the position falls on; the depth at that position.
Dye testing
Introducing a coloured dye at one point and watching where it appears.
To establish whether two points are connected, by observing whether dye introduced at one reaches the other.
Cannot establish: the condition of any pipe; the absence of a connection, from a negative result alone; the route between the two points.
Smoke testing
Introducing a testing vapour into a system to see where it emerges.
To reveal openings connected to the system by observing where the vapour appears above ground or inside a building.
Cannot establish: the condition of a pipe; the responsibility for any opening found; that no opening exists where none was observed.
Pressure or leakage testing
A controlled test of whether a section holds what is put into it.
To assess whether a defined, isolated section retains water or air under a controlled procedure.
Cannot establish: the condition of sections outside the tested length; the cause of any result; compliance, unless the applicable authority says so.
Excavation confirmation
Digging to expose the pipe so it can be seen directly from outside.
To observe the pipe and its surroundings directly, which no remote method can fully substitute for.
Cannot establish: the condition of the line away from the excavation; that no other conditions exist elsewhere.
Municipal record review
Asking the operating authority what its own records show for an address.
To find out what the authority holds: connection records, permit history, maps, and its own statement of where responsibility sits.
Cannot establish: the physical condition of the line; that records are complete; a boundary for a different address or authority.
Permit inspection
An official check of work while it is open or after completion.
To have an authority observe the work against whatever it requires, producing a record independent of the contractor.
Cannot establish: the quality of workmanship beyond what was inspected; that the installation will perform over time.
Engineering or specialist review
A qualified specialist assessing a question beyond ordinary scope.
To bring a qualified opinion to a question that inspection and contractor judgement have not resolved.
Cannot establish: anything beyond the scope actually commissioned; that a dispute will resolve a particular way.
What would change the answer
- nothing to browse this hub
- to apply it: whatever you were given — footage, a report, an invoice with notes
What to do next
It is the method almost every homeowner encounters, and the one whose results are most often over-read.
Start with the camera inspectionIf your situation is different
- You already have footage and want to review it: Review a camera inspection
- You are trying to understand where responsibility sits: Sewer ownership and responsibility
Related, and why
- Camera review
The structured review of an inspection you already hold.
- Comparing proposals
Inspection evidence is what a proposal should be priced against.