Sewer root glossary

A–ZTerms

ABS pipe

Acrylonitrile butadiene styrene, a black plastic pipe used for drains and sewers. Joints are solvent-welded, making them highly resistant to root entry.

Backfill

The soil placed back into a trench after a pipe is laid. It is looser and better aerated than undisturbed soil, so roots travel along it easily.

Backwater valve

A device with a flap that closes to stop sewage from the municipal main flowing back into a building. It does not prevent backups caused by a blockage in your own lateral.

Bell and spigot

A joint where the plain end (spigot) of one pipe sits inside the flared end (bell) of the next. The classic joint in clay and concrete sewer pipe and a common root entry point.

Building drain

The lowest horizontal drain pipe inside a building, collecting from the stacks and carrying wastewater to the building sewer outside the foundation.

Building sewer (lateral)

The pipe that carries wastewater from the building to the municipal main. Also called the sewer lateral or service connection.

Cable machine

A drain cleaning machine that rotates a steel cable with a cutting head. Also called an auger, snake or rooter. Drum and sectional types exist.

Camera inspection

Filming the inside of a sewer line with a push camera to identify roots, cracks, offsets and material. Also called a sewer scope or video inspection.

CIPP lining

Cured-in-place pipe: a resin-saturated tube installed inside an existing pipe and hardened to form a new, jointless pipe that roots cannot enter along its length.

Cleanout

An access fitting with a removable cap that lets equipment enter a drain or sewer line. A main cleanout near the foundation makes root cutting faster and more complete.

Compression joint

A factory-made sealing ring fitted to clay or plastic pipe joints, used from roughly the 1960s onward. More root resistant than mortar or jute until movement or age opens it.

Connection (tap)

The point where a lateral joins the municipal main. A common root entry point that may not be covered by a private-side repair.

Copper sulfate

A chemical sometimes used to kill roots in sewers. It is toxic to aquatic life, can affect wastewater treatment and is restricted or discouraged in many municipalities.

Crown

The inside top of a pipe. Roots often hang from the crown at joints, above the flow line.

Descaling

Mechanically removing hard deposits, roots and scale from the inside of a pipe, often before lining.

Drip line

The ground directly beneath the outer edge of a tree's canopy. Roots commonly extend well beyond it.

Dutch elm disease

A fatal fungal disease of elms spread by bark beetles. Alberta restricts elm pruning in spring and summer to limit its spread.

Feeder roots

Fine, short-lived absorbing roots, often thinner than a pencil lead, that do most of a tree's water uptake and are the first to enter a sewer joint.

Foaming root control

A herbicide product mixed to form a foam that fills the pipe and contacts roots at the crown. Must be registered for the use and applied according to its label.

HDPE pipe

High-density polyethylene pipe joined by heat fusion, producing an effectively jointless line. Commonly used in pipe bursting.

Hydrotropism

The tendency of roots to grow toward moisture. In practice, roots proliferate where moisture is found rather than hunting pipes from a distance.

Infiltration

Groundwater entering a sewer through joints and cracks. Signs of infiltration show the same openings roots can use.

Invert

The inside bottom of a pipe, where flow runs. Chemicals poured down drains mainly travel along the invert.

Jetting root cutter

A cutting head driven by water flow from a high-pressure jetter, used to cut and flush roots from a sewer line.

Jute or oakum

Fibrous packing used in older pipe joints, sometimes with mortar or bitumen. It rots over time, leaving voids that roots exploit.

Locator sonde

A small transmitter in a camera head that lets an operator find the camera's position and depth from the surface.

Mortar joint

A pipe joint packed with cement mortar, common in older clay and concrete sewers. Mortar shrinks and cracks, opening gaps for roots.

NASSCO PACP

The Pipeline Assessment Certification Program, a standard system for coding sewer defects, including root observations, used by many municipalities and inspectors.

Offset joint

A joint where one pipe section has shifted relative to the next, leaving a step and a gap. Roots commonly enter offsets.

Orangeburg pipe

Bituminised fibre pipe used mid-century. It deforms and delaminates over time and is usually replaced rather than lined.

PCP number

The Pest Control Products Act registration number on a pesticide label in Canada, showing the product is registered for the uses on its label.

Pipe bursting

A trenchless method that pulls a new pipe, usually fused HDPE, through the old one while fracturing the old pipe outward.

Point repair

A short sectional liner, often about 1 to 1.5 metres long, cured in place over a single defect such as a root-infested joint.

Property line split

The common division of sewer lateral responsibility at the property line, with the owner responsible on the private side. Varies by municipality.

PVC pipe

Polyvinyl chloride pipe, usually white or green for sewers. Joints may be solvent-welded or gasketed; both resist roots when properly installed.

Reinstatement

Reopening a branch connection after lining by cutting through the liner with a robotic or manual cutter.

Root ball

A dense mass of roots that fills most of the pipe's cross-section. In PACP terms, the most severe root category.

Root barrier

A vertical sheet or panel installed in the soil to deflect roots downward and away from a pipe or structure. Limited protection for deep pipes.

Root saw

A toothed or bladed cable head used to cut roots. Should be sized close to the pipe's inside diameter for a complete cut.

Root suckering

New shoots growing from a tree's roots, common in poplars and aspen. Means living roots can persist after the main trunk is removed.

Sag (belly)

A low section of pipe that holds water and solids. Lining does not correct a sag; replacement or bursting of that section does.

Sectional machine

A cable machine using short, joined cable sections, often used for larger lines and heavy root work.

Sewer backup endorsement

An optional home insurance coverage for water damage from sewer backups. It generally does not pay to repair deteriorated pipe.

Solvent weld

A joint in ABS or PVC pipe made by chemically fusing the pipe and fitting with solvent cement. Highly resistant to roots.

Tap root (PACP)

In PACP coding, a single root entering the pipe, as distinct from fine roots, medium roots or a root ball.

Transition coupling

A rubber coupling with steel bands joining pipes of different materials, such as clay to PVC. A common weak point after partial repairs.

Trenchless repair

Any repair that fixes or replaces a pipe with minimal digging, including CIPP lining, point repairs and pipe bursting.

Vitrified clay pipe

Fired ceramic pipe used for sewers for over a century. The wall resists corrosion well; its many joints are its weakness.