The common sewer defects found on camera are root intrusion, cracks, fractures, offset and separated joints, sags (bellies) that hold water, deposits such as scale and grease, holes, deformation and collapse. Roots and deposits are usually maintenance problems. Fractures, holes, large offsets and collapse are structural and usually lead to repair. Severity depends on size, number and location, not just the defect name.
- Separate defects into structural (the pipe itself is damaged) and operational or maintenance (something inside the pipe restricts flow).
- A defect's name is only half the story; size, extent and whether it is getting worse decide the response.
- Roots almost always mean an open joint or crack, so a root finding is also a structural clue.
- Sags are judged by how deep the standing water is and how long the section runs.
- A single isolated defect in otherwise sound pipe is often a spot repair; the same defect repeated at many joints points toward lining or replacement.
01 /What is the difference between structural and maintenance defects?
Structural defects are damage to the pipe itself: cracks, fractures, breaks, holes, joint displacement, deformation and collapse. Maintenance (operational) defects are things in the pipe that restrict flow: roots, grease, scale, settled debris and obstacles. NASSCO's PACP system grades the two families separately for exactly this reason, and a good residential report keeps them apart too.
02 /What does root intrusion mean?
Root intrusion means tree or shrub roots have found an opening in the pipe, almost always a joint or crack, and are growing inside where water and nutrients are constant. Fine roots are an early sign; a root ball can block most of the pipe. Because roots enter through openings, a root finding is also evidence that a joint is not sealed.
| Level | Appearance | Typical response |
|---|---|---|
| Fine | Hair-like strands at a joint | Cut and monitor; note which trees are nearby |
| Medium | Thicker roots, partly narrowing the pipe | Mechanical cutting or jetting; schedule follow-up |
| Ball / mass | Dense mat blocking much of the cross-section | Clear, then reinspect for damage behind the roots |
| Tap root | A single thick root entering through a crack or joint | Cut; check the entry point for fracture |
Roots come back after cutting because the opening is still there. The long-term fixes seal or replace the joint: lining, spot repair or replacement. SewerRoots.ca covers which trees are worst and prevention in detail.
03 /What do cracks and fractures mean?
A crack is a break line in the pipe wall where the pieces have not moved apart; a fracture is a crack that has opened or where pieces are visibly separating. Cracks are described by direction: longitudinal (along the pipe), circumferential (around it), spiral, or multiple. Fractures are generally graded more severely because they are one step from a broken pipe.
- Longitudinal cracks often come from soil load or pipe crushing, typically at the crown or invert.
- Circumferential cracks often come from settlement or bending stress around a joint.
- Multiple cracks in one location suggest the pipe is under significant stress; watch for deformation.
- Fractures with visible gaps may admit soil and roots and can progress to a break or hole.
A single crack in clay pipe with no soil entering is often monitored or addressed if lining is being done anyway. Multiple fractures in a short stretch lean toward repair. A camera shows the crack but cannot measure whether it leaks; when that matters, as with new or repaired pipe, dye, smoke and pressure testing fills the gap.
04 /What do offset and separated joints mean?
An offset joint means one pipe length has shifted relative to the next, creating a step. A separated (open) joint means the lengths have pulled apart, leaving a gap. Both usually come from ground movement, poor bedding, frost action or root pressure. Offsets are graded by how much the step blocks the pipe; separations by how wide the gap is and whether soil is visible.
| Defect | Mechanism | Typical consequence | Usual next step |
|---|---|---|---|
| Small offset | Minor settlement | Little effect on flow | Note and monitor |
| Medium or large offset | Settlement, heaving, poor bedding | Lip catches paper and debris; roots enter | Spot repair or lining if the offset allows |
| Separated joint | Pipe lengths pulled apart | Soil and roots enter; void can form | Repair, especially if soil visible |
| Separated with soil visible | Open to surrounding ground | Ongoing soil loss; sinkhole risk above | Priority repair |
Large offsets can prevent a liner from sitting properly, which is why lining contractors review the video before quoting.
05 /What does a sag or belly mean?
A sag or belly means a section of pipe has dropped below the intended grade, so water pools instead of draining. On camera, the water line deepens and the lens may go under. Sags form from poor original bedding, settled trench backfill or soil erosion under the pipe.
The seriousness of a sag depends on depth and length. A shallow dip holding water to a small fraction of the pipe diameter may never cause trouble. A long, deep sag collects solids, invites repeated blockages and in shallow or exposed lines can freeze in a Canadian winter. Lining does not correct grade, because the liner follows the host pipe; a deep sag is usually fixed by excavation and re-bedding or replacement. Sags are also the most common structural finding in new plastic laterals, where backfill settles in the first year or two; see sewer scopes on new builds.
06 /What do deposits, scale and grease mean?
Deposits are material that has built up on the pipe wall or settled in the bottom. Attached deposits include grease, scale and encrustation; settled deposits include sand, gravel and debris. They narrow the pipe and catch solids, and heavy buildup can hide cracks or holes.
- Tuberculation / scale in cast iron — corrosion nodules that roughen and narrow the bore. Descaling can restore diameter but can also reveal thin walls.
- Grease — a fat, oil and grease layer from kitchen drains that hardens over time.
- Encrustation — mineral deposits, sometimes at joints where water seeps.
- Settled gravel or soil — often a sign of a break or open joint upstream letting ground in.
- Construction debris — concrete, grout or offcuts, sometimes in new homes.
Cleaning approaches differ by material; PipeCleaning.ca explains which methods suit clay, cast iron and plastic.
07 /What do holes, deformation and collapse mean?
A hole means part of the pipe wall is missing; deformation means the pipe has lost its round shape, usually in flexible pipe or bituminous fibre (Orangeburg) pipe; collapse means the pipe has failed so that its shape is lost and flow is restricted or stopped. These are the most severe structural findings and generally require repair or replacement of that section.
| Finding | Warning signs at home | Usual response |
|---|---|---|
| Hole | Recurring backups, soil in cleanout, depressions in the lawn | Spot repair or replacement of the section |
| Deformation | Slow drains, snagging during cleaning | Assess extent; lining only if the shape allows |
| Collapse | Complete or repeated blockages, camera cannot pass | Excavated or trenchless replacement |
08 /How do you judge how serious a defect is?
Judge seriousness by five factors: type, size, count, location and trend. A defect that is severe in type, large, repeated, located where repair is expensive, and worsening since the last video is urgent. One that is minor, isolated, easy to reach and stable can often wait.
| Factor | Lower concern | Higher concern |
|---|---|---|
| Type | Crack, light roots, light deposits | Fracture, hole, large offset, collapse |
| Size | Small percentage of the cross-section | Large percentage or full circumference |
| Count | One location | Repeated at many joints |
| Location | Shallow, in the yard | Under a driveway, tree, or beyond the property line |
| Trend | Unchanged from earlier video | Worse than earlier video |
Look up specific codes in the inspection report decoder and read what to do after an inspection for the decision path. When you need prices, request a quote.
FAQQuestions people ask
What is the most common sewer defect found on camera?
In older Canadian neighbourhoods with clay laterals and mature trees, root intrusion at joints is one of the most frequently reported findings. Offsets and sags are also common. The mix depends heavily on pipe material and age.
Is a cracked sewer pipe an emergency?
Usually not by itself. A stable crack with no soil entering and no blockage can often be monitored. Fractures, holes, soil infiltration or repeated backups raise the urgency.
Can a belly in a sewer line be fixed without digging?
Generally not. Lining and pipe bursting follow the existing pipe, so they do not correct a dip in grade. Correcting a significant sag typically means excavating that section and re-bedding it.
Do roots mean my pipe is broken?
Roots mean there is an opening, usually a joint that is no longer sealed. The pipe may be otherwise sound, but the opening will keep admitting roots until it is sealed or replaced.
Why does my report say 'structural' and 'O&M' grades?
PACP-style reports grade structural defects and operation and maintenance defects separately so that cleaning needs are not confused with pipe damage.
NETWORKGo deeper across the HAUSE Sewer network
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Permanent fixes for roots in sewer lines: CIPP lining, sectional point repairs, pipe bursting and open-cut replacement compared by cost, lifespan and fit.
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