Sewer inspection glossary

A–ZTerms

ABS

Acrylonitrile butadiene styrene, a black plastic pipe widely used for drain, waste and vent piping inside Canadian houses.

Asbestos-cement pipe

A grey cement pipe reinforced with asbestos fibres, used in some municipal water and sewer systems. It should not be cut or broken without proper controls.

Belly

Another word for a sag: a section of pipe below the intended grade where water pools. On camera, the water deepens and the lens may go under.

Bituminous fibre pipe

Pipe made of wood or paper fibre impregnated with tar pitch, often called by the trade name Orangeburg. It tends to deform into an oval and is generally treated as end-of-life when found.

Building drain

The lowest horizontal piping inside a building that collects waste from stacks and branches and carries it to the building sewer outside the foundation.

Building sewer

The pipe from just outside the building's foundation wall to the municipal sewer or private disposal system; often called the lateral or service line.

Building trap

A U-shaped trap on the building drain, found in some older houses, with two cleanout plugs set in the basement floor. Also called a house trap or running trap; it blocks most camera heads.

Cast iron

A heavy metal pipe common in older houses for stacks and building drains. It corrodes from the inside, forming scale and tuberculation, and can crack along the bottom.

Channelling

A groove worn along the bottom of a cast iron pipe by corrosion and flow, which can thin the wall and lead to holes or longitudinal cracks.

CIPP

Cured-in-place pipe: a resin-saturated liner inserted into an existing pipe and cured to form a new pipe inside the old one. It follows the host pipe, so it does not correct sags.

Cleanout

A capped fitting that gives access to a drain or sewer for cleaning and inspection. The main cleanout is the usual camera entry point.

Clock position

A way to describe where a defect sits around the pipe, as if looking downstream at a clock face: 12 o'clock is the top, 6 o'clock the bottom.

Collapse

Failure of the pipe so that its shape is lost and flow is restricted or blocked. Usually requires replacement of the section.

Crack

A visible break line in the pipe wall where the pieces have not moved apart. Described as longitudinal, circumferential, spiral or multiple.

Crawler camera

A motorized camera on wheels or tracks, driven remotely through larger pipes such as municipal mains. Rarely used for house laterals.

Crown

The top inside surface of a pipe, at 12 o'clock.

Deformation

Loss of a pipe's round shape, usually in flexible plastic or fibre pipe under soil load. Severe deformation can prevent lining.

Deposits

Material in the pipe: attached (grease, scale, encrustation) or settled (sand, gravel, debris). An operation and maintenance defect.

Descaling

Mechanical removal of scale and tuberculation from cast iron pipe, often before lining. It can reveal thin walls or holes.

Dye test

A diagnostic in which coloured tracer dye is flushed into one drain, downspout or sump and the likely outlets are watched to see where the water actually goes.

Encrustation

Hard mineral deposits on the pipe wall, often around joints or cracks where groundwater seeps in.

Footage counter

The on-screen distance reading showing how much camera cable has been paid out from the reel, used to locate observations along the pipe.

Fracture

A crack that has visibly opened or where the pipe pieces have begun to separate. More severe than a crack.

Grade (PACP)

A severity rating from 1 (minor) to 5 (most severe) given to each coded defect, with structural and O&M defects graded separately.

Grade (slope)

The downward slope of a pipe that lets wastewater flow by gravity. Loss of grade causes sags.

Hole

An opening in the pipe wall where material is missing, often with soil visible behind it.

Infiltration

Groundwater entering the pipe through defects or joints. PACP-style codes describe it as weeper, dripper, runner or gusher by rate.

Inspection chamber

A shallow buried box with a removable cover where drains meet, common in British practice. It gives rod and camera access but is not meant for a person to enter.

Inspection opening

The Australian and New Zealand term for a capped access fitting on a drain, sometimes called an inspection point. The Canadian equivalent is a cleanout.

Invert

The bottom inside surface of a pipe, at 6 o'clock, where the flow runs.

Joint

The connection between two lengths of pipe. Older clay pipe has many joints; plastic pipe has fewer.

LACP

NASSCO's Lateral Assessment Certification Program, applying standardized condition coding to service laterals.

Lateral

The service pipe connecting a building to the municipal main; also called the building sewer or service connection.

Lateral launch camera

A small camera deployed from a mainline crawler into a service connection, letting crews inspect the start of a lateral from the main without entering the building.

Locator

A hand-held receiver that detects the sonde signal from above ground to find the camera head's position and estimate depth.

MACP

NASSCO's Manhole Assessment Certification Program, for coding manhole condition.

Main (municipal sewer main)

The public sewer pipe, usually under the street or lane, into which laterals connect.

NASSCO

A North American association for the underground pipeline rehabilitation industry that runs the PACP, LACP and MACP training and certification programs.

O&M defect

Operation and maintenance defect: something in the pipe that restricts flow, such as roots, grease or debris, as distinct from damage to the pipe.

Offset joint

A joint where one pipe length has shifted relative to the next, forming a step that can catch solids and admit roots.

Orangeburg

Trade name commonly used for bituminous fibre sewer pipe. See bituminous fibre pipe.

PACP

NASSCO's Pipeline Assessment Certification Program, the North American standard for coding and grading sewer pipe conditions.

Pipe bursting

A trenchless replacement method that pulls a new pipe through the old one, breaking the old pipe outward.

Push camera

The standard residential sewer camera: a camera head on a semi-rigid cable pushed by hand through the pipe.

PVC

Polyvinyl chloride, a plastic pipe, commonly white or green, widely used for exterior sewer laterals since roughly the 1970s and 1980s.

Quick rating

A PACP-style four-character summary of a pipe's defects: the highest grade and its count, then the next-highest grade and its count.

Root intrusion

Tree or shrub roots growing into a pipe through a joint or crack. Graded from fine roots to a root ball.

Sag

A section of pipe that has dropped below grade and holds water. Judged by maximum water depth and length.

Separated joint

A joint where pipe lengths have pulled apart, leaving a gap through which soil and roots may enter.

Service connection (tie-in)

The point where the lateral joins the municipal main.

Smoke test

A test in which harmless visible smoke is blown into a sewer or drain system to show where it escapes: roof vents are normal, while lawns, downspouts or indoor fixtures point to breaks, improper connections or dry traps.

Sonde

A small radio transmitter in or behind the camera head that a locator detects from above ground. Many residential systems use 512 Hz.

Spot repair

Repair of a short section of pipe at a specific defect, by excavation or a short internal liner.

Spring line

The horizontal midline of a pipe, at 3 and 9 o'clock.

Stack

A vertical drain pipe inside the building that carries waste down from upper fixtures to the building drain.

Surcharge

A condition where a sewer main flows full and under pressure, which can push wastewater back up service laterals.

Transition

A change in pipe material or size along a line, such as clay to PVC, often marking a past repair.

Tuberculation

Corrosion nodules on the inside of cast iron pipe that roughen and narrow the bore.

Vitrified clay pipe

Fired clay pipe, durable and chemically resistant, common in older laterals. Its weak points are the joints.

Wye

A Y-shaped fitting where a branch joins a drain at an angle. On camera, a wye opening can be mistaken for a hole.