This drain augering glossary defines the equipment, pipe parts and defects you meet when snaking a drain, in plain language. It covers auger classes and cable types, cutting heads, the parts of a house drain from the fixture trap to the lateral, and the defects that make clogs come back, so you can read a quote or talk to a drain cleaner with confidence.
- Equipment terms describe what the machine is; pipe terms describe where the clog is.
- Knowing the pipe part (trap, branch, stack, building drain, lateral) tells you which auger and cable to use.
- Defect terms (belly, offset, tuberculation) explain why a clog keeps returning.
01 /How to use this glossary
Terms are grouped loosely: equipment first, then the parts of a house drain, then the defects and conditions that cause clogs to return. Where a term has a deeper guide, the definition links to it in the related pages below. For sizing any piece of equipment, see the auger cable size chart; for diagnosing where a clog sits, use the Clog Locator.
Drain cleaners, plumbers and rental counters do not always use these words the same way. "Snake" and "auger" are used interchangeably by most people, while some tradespeople reserve "rodding" for sectional machines. If a quote uses a term you do not recognise, ask what it means in that contractor's usage. The definitions below describe the common Canadian residential meaning.
Sizes are given as nominal pipe sizes in inches with metric equivalents where useful, since Canadian trades still quote drain pipe in inches while municipalities often use millimetres. A 4-inch building drain and a 100 mm building drain are the same pipe.
A–ZTerms
- ABS
- Acrylonitrile butadiene styrene, the black plastic drain pipe common in Canadian houses from about the 1970s onward.
- Auger (drain auger)
- A tool that clears drains by rotating a flexible steel cable inside the pipe. Also called a snake, drain snake or plumber's snake.
- Backwater valve
- A valve with a flap that closes against sewage flowing backward from the main. Must be opened or bypassed for augering, never forced through.
- Belly (sag)
- A section of pipe that has settled lower than the rest, holding water and solids. Augering clears it temporarily; it refills.
- Branch drain
- A drain line that serves a group of fixtures, such as one bathroom or the kitchen, and connects to the stack or building drain.
- Building drain
- The horizontal drain inside the house, under or along the basement floor, collecting all fixtures and carrying them to the building sewer.
- Building sewer (lateral)
- The pipe from the house foundation to the municipal sewer main or a septic system. Often 4 inch (100 mm).
- Bulb head
- A small bulb-shaped coil head that steers through traps and catches hair in small drains.
- C-cutter
- A C-shaped or U-shaped cutting blade that opens a wider channel in soft buildup.
- Cable
- The coiled spring-steel shaft of an auger that carries torque from the drive to the head. Sized by outside diameter, from about 1/4 inch to 1-1/4 inch.
- Cable mitts
- Leather augering gloves with reinforced palms, recommended by manufacturers for guiding rotating cable. Cotton or knit gloves are unsafe on powered augers.
- Camera inspection
- Running a push camera through a drain to see its condition, locate defects and measure distances. Best done right after clearing.
- Chuck
- The part of the auger that grips the cable so it rotates with the drive. On hand drums it is often a thumbscrew.
- Cleanout
- A capped opening in the drain system that gives access for augering or inspection. Found at stack bases, basement floors and outside.
- Closet auger
- A toilet auger: a short cable in a rigid curved tube with a rubber or vinyl guard that protects the porcelain and aims the cable into the trapway.
- Closet bend
- The elbow below a toilet that connects the toilet flange to the drain, typically 3 inch.
- Drill-powered auger
- A small drum auger driven by a cordless drill. Faster than hand cranking, but must be run at low speed to avoid kinking thin cable.
- Drop-head auger
- A compact powered auger with a flat drum and top-mounted cable guide, used in small lines where space is tight. Also called a flat-top machine.
- Drum machine
- An electric auger with one continuous cable coiled inside a rotating drum. The common machine for branches, stacks and building drains up to about 4 or 6 inches.
- Flexible leader
- A short length of very flexible cable fitted between the main cable and the head to help it pass tight bends.
- Floor drain
- A drain set in the basement slab with a trap below. Usually the lowest opening in the house, so it shows main-line backups first.
- FOG
- Fats, oils and grease. Harden on pipe walls and cause repeat clogs that augering opens but does not remove.
- Foot pedal (foot switch)
- A pedal, usually air-operated, that starts and stops rotation so the operator can keep both hands on the cable and stop instantly.
- GFCI
- Ground-fault circuit interrupter. An outlet or adapter that cuts power quickly if current leaks to ground; recommended for powered augers near water.
- Grabber (retrieving head)
- A head designed to snag wipes, rags and fibrous material so it can be pulled out rather than pushed further.
- Guide tube (guide hose)
- A tube at the front of a drum machine or a fitting in the cleanout that directs the cable and limits whipping.
- Hand drum auger
- A hand-cranked auger that stores 1/4-inch cable in a drum. Suited to sink, tub and shower drains up to about 2 inches.
- Head (tool, bit)
- The working tip of an auger cable: probing, cutting or retrieving. Swappable on most powered machines.
- Hollow-core cable
- Auger cable with no inner wire. Flexible and good for tight bends such as sink traps, but more prone to kinking under load.
- Hydro jetting
- Cleaning a pipe with high-pressure water through a nozzle. Scours the full pipe wall; better than augering for grease and sludge.
- Hydrogen sulfide (H₂S)
- A toxic sewer gas with a rotten-egg smell that can dull the sense of smell at higher concentrations. Ventilate and never enter confined spaces.
- Inner-core cable
- Auger cable with an inner wire coil or strand. Stiffer, carries more torque and resists stretching and kinking.
- Municipal main
- The public sewer pipe, usually under the street, that laterals connect to.
- Offset joint
- A joint where one pipe section has shifted relative to the next, creating a lip that catches debris and auger heads.
- Orangeburg (bituminous fibre pipe)
- Tar-impregnated fibre pipe used in some mid-century houses. Deforms with age; aggressive cutters can tear it.
- Power feed (automatic feed)
- A mechanism on some machines that advances and retracts the spinning cable with a lever, keeping hands further from the cable.
- Rodding
- Clearing a drain with a rotating cable, a term some trades use especially for sectional machines and main lines.
- Root intrusion
- Tree roots growing into a sewer pipe through joints or cracks, forming masses that catch paper and solids.
- Root saw
- A toothed cutting head that shears tree roots growing into a sewer pipe. Clears flow but does not stop roots regrowing.
- Running trap (house trap)
- A U-shaped trap on the building drain in some older houses, with two plugs. Augering toward the street is done through the downstream plug.
- Sectional machine
- An electric auger that spins short, heavy cable sections coupled together as they are fed in. Used for main lines, long laterals and roots.
- Snaking
- Common name for augering a drain. Used interchangeably with augering by most homeowners and many trades.
- Spade head
- A flat arrow-shaped cutting head for boring through packed paper, sludge and grease plugs.
- Stack
- The main vertical drain pipe carrying waste from upper floors down to the building drain. Typically 3 inch in houses.
- Stored torque
- Twist that builds up in an auger cable when the head stops but the drive keeps turning. The main cause of cable looping and hand injuries.
- Toilet pull
- Removing a toilet to use its floor opening as a straight access point for augering a branch or main.
- Trap (P-trap)
- The U-shaped bend under a fixture that holds a water seal to block sewer gas. The most common place for sink and tub clogs.
- Trap arm
- The short horizontal pipe from the trap to the drain in the wall. A common clog point just beyond the trap.
- Trap primer
- A device that adds water to a floor drain trap automatically to keep its seal from drying out.
- Trap seal
- The water held in a trap. If it evaporates, sewer gas can enter the room.
- Trapway
- The built-in trap passage cast inside a toilet's porcelain.
- Tuberculation (scale)
- Lumpy corrosion buildup inside cast iron pipe that narrows it and catches debris. Requires descaling rather than standard augering.
- Vent
- Pipes that let air into the drain system so water flows freely and traps are not siphoned. A blocked vent causes slow drains and gurgling.
- Vitrified clay pipe
- Fired clay sewer pipe common in older laterals. Hard-walled, but its joints are vulnerable to roots.
FAQQuestions people ask
What is the difference between a snake and an auger?
For most purposes, none. Both describe a rotating cable used to clear drains. Some trades use "auger" for drum machines and "rodding" for sectional machines.
What does lateral mean in drain work?
The building sewer: the pipe from your foundation to the municipal main or septic system. It is usually the largest and longest drain on the property.
What does a cleanout look like?
A threaded plug or screw cap on a Y or T fitting, typically 3 or 4 inches across, at the base of the stack, in the basement floor or on a riser outside.
What is tuberculation in a drain pipe?
Corrosion buildup on the inside of cast iron pipe. It narrows the pipe and catches debris, and needs descaling rather than standard augering.