Cracked Sewer Pipe: Reading Cracks, Fractures and Breaks
A crack is a break line in the pipe wall. What matters is how far it has gone: a hairline crack where the pipe still holds together, a fracture that has opened up, a broken section with pieces displaced, or a full collapse. On camera, you read that progression from how visible the line is, whether the pieces have moved, and whether you can see soil or a void behind the wall.
Why sewer pipes crack
- Soil load and traffic. Shallow pipe under driveways and streets takes load it may not have been designed for.
- Settlement. Ground movement bends the pipe, often cracking it around the circumference near joints. A sagging line (belly) often shows this.
- Roots. Roots growing in a joint or crack widen it over time. See root intrusion.
- Corrosion. Cast iron thins along the invert and cracks along the edges of the channel. See cast iron pipe corrosion.
- Outside damage. Excavation, a bore passing too close, or heavy equipment.
- Material age. Clay and older concrete are rigid and brittle; they crack rather than deform.
Crack types by direction
- Longitudinal: runs along the length of the pipe, often at the crown, invert or springline. A classic sign of the pipe carrying too much soil load.
- Circumferential: runs around the pipe, often from bending or settlement.
- Multiple: a mix of cracks in one area, which can break the wall into pieces.
- Spiral: winds around the pipe, changing clock position along its length.
Severity: crack, fracture, broken, collapse
Structural defects in PACP sit in separate code families that roughly follow the damage progression. The codes below come from the PACP 7 color-coded chart. The exact definitions of crack versus fracture, and the grades each one earns, are in the PACP manual for the version you code to.
| Level | What you see | PACP codes | Typical recommendation |
|---|---|---|---|
| Crack | Visible line, wall pieces still together | CL, CC, CM, CS, CH (hinge) | Record, monitor or line |
| Fracture | Crack visibly opened, pieces not displaced | FL, FC, FM, FS, FH (hinge) | Line, or spot repair if localized |
| Broken | Pieces displaced or missing | BSV (soil visible), BVV (void visible) | Spot repair or replace; line only if the shape allows |
| Hole | Opening in the wall | HSV (soil visible), HVV (void visible) | Spot repair or line, depending on size |
| Deformed | Pipe out of round | DR (rigid pipe) | Repair soon; can progress to collapse |
| Collapse | Pipe has lost its shape and flow area | X | Excavate and replace |
A few field notes that help the report:
- Stop and light it. Hairline cracks disappear in a moving shot. Stop the head and rotate or adjust lighting.
- Log clock positions. A crack from 11 to 1 o’clock at the crown reads differently than one at the invert.
- Look behind the wall. Soil, gravel, roots or a dark void behind a break raise the urgency: the ground around the pipe is washing in.
- Watch for water. Running or dripping infiltration at a crack is recorded separately in PACP’s Infiltration family.
- Don’t force it. If the pipe is broken or collapsing, pushing a camera or a cutter through can make it worse and can get the head stuck.
Repair options by severity
Monitor. Isolated hairline cracks in a round pipe with no infiltration, roots or soil can be recorded and re-scoped later. Put the footage and clock position in the report so the next scope compares the same spot.
Line. Cured-in-place lining is a common fix for cracked and fractured pipe that still holds its shape. It seals the cracks and adds structure. Broken sections with missing pieces may need a spot repair first.
Spot repair. A dig at one footage to replace a broken section. The sonde locate from your camera tells the crew where to dig. See sewer cameras with a locator.
Replace. Collapses, deformed pipe, and lines cracked or broken along much of their length. Open cut or pipe bursting, depending on the site.
What to tell the customer
Customers hear “crack” and picture a failed pipe. Put it in order for them: where the crack is, how big it is compared with the rest of the line, whether anything is coming through it, and what happens if they wait. A single hairline crack in a round pipe is a note in the report. A fracture with soil behind it is a repair. A broken or collapsing section is urgent. Showing the video at the stopped frame, with the footage on screen, does more than any description.
A crack in a report means little without a location. Give every structural finding a footage, a clock position and, where you can, a surface mark. That's what turns a video into a repair quote.
Cracks near a trenchless utility path deserve a second look: NASSCO’s cross bore guidance points out that cracks and fractures near a bore can indicate a near miss. See cross bore.
FAQ
Is a longitudinal crack worse than a circumferential one?
Not automatically. A circumferential crack often comes from bending or settlement and can stay stable. A longitudinal crack running along the pipe can mean the pipe is carrying more soil load than it should, and several of them around the pipe can let it break into pieces. Look at how many there are, whether they have opened, and whether the pipe is losing shape.
Can a cracked pipe be lined?
Usually, if the pipe still holds its shape and there are no large pieces missing. Cracks and fractures are a common reason for cured-in-place lining. Broken sections with missing pieces, voids or deformation may need a spot repair first.
How do I know if a crack is leaking?
Look for water running or dripping in at the crack, staining, roots or soil coming through, or a void visible behind it. Infiltration is its own group of codes in PACP. A dry crack with no staining is less urgent than one with water or soil moving through it.
What is a hinge crack?
PACP includes a hinge descriptor for cracks and fractures that divide the pipe wall into sections that can move like a hinge. It is a sign the pipe is close to breaking. Check the PACP manual for the exact definition and how it is counted.