Free sewer scope cheat sheet — defect codes & severity thresholds

Severity scale & pipe grade

Every finding gets a severity; the pipe gets a 1–5 grade from the worst finding. Structural findings carry their own weight table (a structural moderate is a 3, not a 4) so that a 5% liner wrinkle and a collapsed pipe never land on the same grade.

Severity	Threshold (documented)	Action window
Minor	No meaningful loss of flow capacity — observation only	Monitor at next service
Moderate	~10–25% loss of cross-section	Correct within 12 months
Major	~25–50% loss, broken/missing wall, offset or gap ≥ 1 in, will worsen with use	Priority repair, within 30 days
Critical	Collapse, >50% blockage, active soil loss / void, sewage backup now	Immediate — 24–48 hours

Pipe grade	1	2	3	4	5
Meaning	Excellent	Good	Fair	Poor	Immediate attention
Driven by	No defects	Minor O&M, or a minor structural item	Moderate O&M, or a moderate structural item (offset < 1 in, hairline crack, small liner wrinkle)	Major structural (offset ≥ 1 in, missing wall, ≥ 10% wrinkle), or a major O&M blockage	Critical structural only — collapse, void / soil loss; a critical O&M blockage tops out at 4

Defect codes

M- = operation & maintenance (clean / monitor). S- = structural (repair). C- = context, not a defect.

Code	Defect	Class	Severity is driven by
`M-R`	Root Intrusion	O&M	% of bore: <10 minor · 10–25 moderate · 25–50 major · ≥50 or active backup critical
`M-G`	Grease Buildup	O&M	% of bore, and whether flow is backing up
`M-DB`	Debris Blockage	O&M	% of bore, and whether flow is backing up
`M-SC`	Scale / Tuberculation	O&M	% loss: <25 minor · 25–50 moderate · ≥50 major
`M-W`	Standing Water / Belly	O&M	Depth and whether it backs up · backup = major
`M-II`	Infiltration / Inflow	O&M	Active flow through the defect raises it to major
`M-SD`	Sediment / Grit	O&M	Minor unless it is blocking flow
`S-OJ`	Offset Joint	Structural	Offset ≥ 1 in or soil entry = major · ≥ 1/2 in = moderate · less = minor
`S-JS`	Joint Separation	Structural	Gap ≥ 1 in or soil entry = major · otherwise moderate
`S-CR`	Crack	Structural	Hairline = moderate · through-wall / displaced / missing piece = major
`S-BR`	Broken Pipe	Structural	Missing wall = major · void or soil loss behind it = critical
`S-CL`	Collapse	Structural	Always critical
`S-DF`	Deformation / Ovality	Structural	Moderate · severe or flattened = major
`S-WR`	Wrinkle / Liner Defect (CIPP)	Structural	% of pipe diameter: <5 minor · 5–10 moderate · ≥10 or restricting flow = major
`S-DT`	Deterioration	Structural	Wall loss drives it: spalling / crumbling / exposed aggregate / heavy corrosion = major · "surface etching only, no loss of wall material" = minor · otherwise moderate
`S-OB`	Orangeburg Deterioration	Structural	Major (this material has no service life left)
`S-VD`	Void / Soil Intrusion	Structural	Always critical — soil is leaving the trench
`C-MT`	Pipe Material Transition	Context	Minor · moderate if soil is entering at the coupling
`C-SN`	Sonde / Tap Marker	Context	Minor — location marker only

How to describe the 12 findings we see most

1. Root Intrusion · `M-R`

See: hair-like to thick roots at joints or through the wall

Severity: <10% bore minor · 10–25% moderate · 25–50% major · ≥50% or water backing up critical

Describe: "Root intrusion at [location], ~[X]% of pipe diameter, [water backing up / flow unrestricted]."

Recommend: mechanical cutting, then root inhibitor and/or spot repair to prevent recurrence.

2. Crack vs Broken Pipe · `S-CR` / `S-BR`

See: hairline crack, through-wall crack, missing piece, hole

Severity: hairline moderate · through-wall / missing wall major · void or soil loss critical

Describe: "[Longitudinal / circumferential] crack ~[length] at [clock position], [through wall / surface only], no soil visible."

Recommend: spot repair or CIPP lining; excavation if the wall is missing and soil is moving.

3. Offset Joint · `S-OJ`

See: adjacent sections out of alignment at a joint

Severity: <1/2 in minor · 1/2–1 in moderate · ≥1 in or soil entry major

Describe: "Offset of ~[X] in at the [clock] position, [soil entering / no gap visible]."

Recommend: evaluate for settlement; spot repair or lining where the offset can catch debris.

4. Joint Separation · `S-JS`

See: gap where sections pulled apart

Severity: moderate · ≥1 in gap or soil entering = major

Describe: "Joint separation of ~[X] in at [location], [soil entering / no soil visible]."

Recommend: spot repair and check the adjacent joints for the same movement.

5. Collapse · `S-CL`

See: full structural failure, flow blocked

Severity: always critical

Describe: "Pipe collapse at [location]; line [partially / fully] obstructed, camera could not pass."

Recommend: excavate and replace; re-inspect after repair. Report the section as not inspected.

6. Void & Soil Intrusion · `S-VD`

See: soil entering the pipe, missing bedding, a void behind the wall

Severity: always critical — the trench is losing support

Describe: "Soil entering through the defect at [location]; void visible behind the wall."

Recommend: immediate evaluation for excavation / structural repair; check for sinkhole risk at the surface.

7. Standing Water / Belly · `M-W`

See: water pooling in a low spot that will not drain

Severity: moderate · major once it backs flow up

Describe: "Standing water ~[depth] at [location], no slope visible for ~[length] — belly / low spot."

Recommend: confirm the grade; correct the low point (re-lay or lining with a structural liner).

8. Scale / Tuberculation · `M-SC`

See: hard deposits or rust scale reducing the diameter (typical in cast iron)

Severity: <25% minor · 25–50% moderate · ≥50% major

Describe: "[Light / moderate / heavy] tuberculation on the invert, ~[X]% cross-section loss."

Recommend: hydro-jet / descale; lining where wall loss is significant.

9. Grease Buildup · `M-G`

See: grease or FOG coating the walls, often with a downstream restriction

Severity: 25–50% major once it restricts flow; ≥50% or backup critical

Describe: "Grease buildup occupying ~[X]% of the bore at [location]."

Recommend: jet and CCTV-verify; address the source (kitchen / restaurant discharge).

10. Debris Blockage · `M-DB`

See: wipes, rags, construction debris caught at a joint

Severity: moderate · major at 25–50% · critical above 50% or with backup

Describe: "[Material] caught at [location], restricting flow to ~[X]% of the bore."

Recommend: cable / jet to clear, then re-inspect to confirm the pipe behind it.

11. Orangeburg / Clay Tile Deterioration · `S-OB` / `S-DT`

See: deforming, crumbling or delaminated Orangeburg; cracked and root-friendly clay tile

Severity: major — repair, not maintenance

Describe: "[Material] with [crushing / delamination / missing sections] from [location] to [location]."

Recommend: plan replacement or a full-length structural liner; patch repairs rarely last in this material.

12. Infiltration / Inflow · `M-II`

See: water entering through a defect while there is no flow from the house

Severity: moderate · major if it is flowing actively

Describe: "Water entering through the [defect] at [location], observed with no fixture running."

Recommend: seal the defect (spot repair / lining); it is a wet-weather surcharge risk.

Before you issue the report

Check	Why it matters
Scope & limitations written, including the section the camera never reached	A report without it reads as if you saw the whole line — that is the weakest legal link in a scope report
Total length inspected + distance to the city tap	Contractors bid from these numbers
Every finding has a distance in feet and a clock position	Localisation is the whole point of the video
Structural findings separated from O&M findings	The client needs to know what to repair vs what to clean
Recommendations in priority order, with a time window	"Needs repair" alone gets ignored by buyers and realtors
At least one still per defect showing the camera footer (distance / depth / time)	That footer is what settles a dispute later; keep the original video too
Report number, license number, page identification, signature line	Traceability of the document itself

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This cheat sheet is a writing aid, not engineering advice, and it is not a substitute for PACP certification. Confirm every finding from the actual video.
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Severity scale & pipe grade

Defect codes

How to describe the 12 findings we see most

1. Root Intrusion · M-R

2. Crack vs Broken Pipe · S-CR / S-BR

3. Offset Joint · S-OJ

4. Joint Separation · S-JS

5. Collapse · S-CL

6. Void & Soil Intrusion · S-VD

7. Standing Water / Belly · M-W

8. Scale / Tuberculation · M-SC

9. Grease Buildup · M-G

10. Debris Blockage · M-DB

11. Orangeburg / Clay Tile Deterioration · S-OB / S-DT

12. Infiltration / Inflow · M-II