Sewer cleaning glossary

A–ZTerms

ABS

Acrylonitrile butadiene styrene, a black plastic drain pipe common in Canadian homes from roughly the 1970s onward. Smooth, root-resistant joints when glued properly.

Access riser

The vertical sleeve or box running from a floor-level cover down to a buried backwater valve or cleanout, so it can be reached without breaking concrete.

Auger

A cable machine that spins a flexible steel cable with a head on the end to break up or retrieve blockages. Also called a snake.

Backflow

Flow in the wrong direction, from the municipal sewer back toward the house.

Backwater valve

A one-way valve on the building sewer that lets wastewater out and closes to stop sewage flowing back in from the municipal side.

Belly

Another word for a sag: a low section of pipe where water and solids collect.

Building drain

The lowest horizontal drain pipe inside the building that collects waste from the stacks and carries it out to the building sewer.

Building sewer

The pipe that runs from just outside the foundation wall to the municipal sewer or private system. Often called the lateral.

Cable machine

Motorized equipment that rotates a steel cable through a drain or sewer; drum and sectional types are common.

Camera inspection

A video inspection of the inside of a pipe using a waterproof camera on a push rod or crawler, with a footage counter.

Cast iron

A heavy metal drain pipe common in older Canadian homes. Durable, but the interior can scale and corrode over decades.

Cleanout

A capped fitting that gives access to a drain or sewer for cleaning and inspection. The main cleanout is usually near where the line leaves the house.

Combined sewer

A municipal sewer designed to carry wastewater and storm water in the same pipe. Found in older parts of some Canadian cities and more prone to wet-weather backups.

Confined space

An enclosed area not designed for continuous occupancy, such as a manhole, pit or large interceptor, where gas or low oxygen can be deadly. Entry is regulated under occupational health and safety rules.

Cutter head

A cable attachment with blades that cut roots and hardened material from the pipe wall.

Descaling

Removing hardened scale and corrosion from the inside of cast iron pipe, often with chain knockers or specialized heads.

Drum machine

A cable machine that stores its cable coiled inside a rotating drum; convenient for residential lines.

Ejector pump

A pump in a sealed basin that lifts sewage from fixtures below the sewer line up to the building drain.

Enzyme cleaner

A drain product containing bacteria or enzymes that digest some organic matter. Not a substitute for mechanical cleaning of a main line.

Floor drain

A drain set in the basement floor, usually the lowest opening in the house and the first place a main-line backup appears.

Flow test

Running several fixtures at once while watching the lowest drain, to confirm a line is clear after cleaning.

FOG

Fats, oils and grease: kitchen waste that congeals in pipes and a leading cause of blockages.

Footage counter

The distance display on a camera or cable machine, showing how far into the line the head has travelled.

Grease interceptor

A tank that separates grease and solids from kitchen wastewater before it reaches the sewer; required for many food service businesses.

Grease trap

A smaller grease interceptor, usually under or near a sink.

Hydro jetting

Cleaning a pipe with high-pressure water through a nozzle whose rear jets pull the hose forward and scour the pipe wall.

Hydrogen sulphide

H2S, a toxic gas produced in sewers. Smells of rotten eggs at low levels but can deaden the sense of smell at higher, more dangerous levels.

Infiltration

Groundwater entering a sewer through cracks, joints and defects.

Inflow

Surface water entering a sanitary sewer through direct connections such as roof leaders, some foundation drains or manhole lids.

Invert

The inside bottom of a pipe, where flow runs and solids settle.

Lateral

The private service pipe that connects a building to the municipal main. Ownership may be split at the property line or elsewhere, depending on the municipality.

Locator

An above-ground receiver used to find a sonde in a camera head or cable, marking a pipe's location and approximate depth.

Main

The municipal sewer pipe, usually under the street or lane, that collects flow from many service connections.

Maintenance interval

The planned time between professional cleanings, set by the line's condition and history.

NASSCO PACP

The Pipeline Assessment Certification Program from NASSCO, a widely used standard for coding defects observed in sewer camera inspections.

Normally open valve

A backwater valve whose flap rests open and closes only when backwater lifts it.

Offset joint

A joint where two pipe sections no longer line up, creating a lip that catches debris.

Orangeburg

Bituminous fibre pipe used in some mid-twentieth-century homes. Prone to deformation and collapse; aggressive cleaning can damage it.

Overland flooding

Water that enters a building over the ground surface, such as through windows, doors or window wells. Insurers usually treat it as a separate peril from sewer backup.

PVC

Polyvinyl chloride, a white or green plastic sewer pipe common in modern construction; smooth and root-resistant when properly installed.

Root intrusion

Tree roots entering a pipe through joints or cracks and growing into a mass that catches solids.

Root saw

A cable head with teeth designed to cut roots cleanly from the pipe wall.

Sag

A low spot in a pipe where water stands and solids settle, usually from settlement or poor bedding.

Scale

Hard corrosion and mineral buildup on the interior of cast iron pipe, which roughens and narrows it.

Sectional machine

A cable machine that uses short cable sections joined together, suited to longer and larger lines.

Sewer backup endorsement

An optional add-on to a home, condo or tenant insurance policy that covers damage from water or sewage backing up through drains, usually with its own limit and deductible.

Sonde

A small transmitter in a camera head or on a cable that a locator can detect from above ground.

Stack

A vertical drain pipe that carries waste from upper floors down to the building drain; kitchen stacks in multi-unit buildings collect grease.

Sump pump

A pump that removes groundwater from a pit, usually fed by foundation drainage, and discharges it away from the house.

Surcharge

When a sewer main is full beyond capacity and the water level rises in connected pipes, which can push sewage back into homes.

Trap seal

The water held in a fixture trap that blocks sewer gas from entering the house. Dries out in rarely used drains.

Vent stack

A pipe, usually exiting through the roof, that admits air to the drainage system so water flows smoothly and traps are not siphoned.

Vitrified clay pipe

Fired clay sewer pipe common in older homes; resists chemicals but its joints admit roots.

Weeping tile

Perforated foundation drain pipe around the footing that collects groundwater, usually routed to a sump pit.