Plumbing Terminology 101

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March 22, 2024 by Henry Parker

If you’ve ever consulted with a plumber or taken a trip to the hardware store for a bit of DIY plumbing you’ve probably encountered numerous confusing terms.

This problem becomes even more apparent when you consider that homes can have different types of septic systems, each with their own unique features. The following glossary contains both common an uncommon plumbing terms, alphabetized and broken down into categories for easier searching.

Common Plumbing Terms

Bleed: to release excess air in a pipe by opening a valve at the end.
Brass: generic slang term for any faucet or fixture.
Branch Drain: fixture drain which leads to the main drain pipeline.
Effluent: liquid waste in a septic system.
Fitting: term used to describe any part that connects two sections of pipe.
Flow Rate: how much water flows through a plumbing system; measured in either gallons per minute (GPM) or per hour (GPH).
Gallons per Flush (GPF): measurement of water needed to flush; used to regulate toilets and flush valves; 1.6 GPF is the current legal maximum permitted for new toilets.
Gray Water: water waste from non-toilet fixtures.
KiloPascal (kPa): metric unit of pressure equaling 1/ 100th of an atmosphere.
Maximum Containment Level (MCL): maximum amount of a contaminant permitted in a water supply by law.
Non-Ferrous: contains no iron.
Potable: water which is safe to consume.
Pressure Head: unit of measure for pressure in a plumbing system describing the vertical force caused by water at a depth of one foot.
Riser: vertical supply pipes which bring water from the branch to a fixture or to a higher floor.
Sediment: debris that settles at the bottom of water tanks.
Soil Pipe: pipe carrying waste from a toilet.
Trap Seal: the water in a trap which serves as a liquid seal.
Trap Weir: the highest point for water before it drains in both P-traps and S-traps.
Water Hammer: a loud banging sound caused when the water supply is suddenly cut off from a fixture, causing hydraulic shock.

Plumbing Components and Fixtures

Aerator: insert screwed onto a faucet nozzle that reduces splashing by mixing air into the flowing water.
Ball Check Valve: valve which employs a ball which can seal against a seat to stop the flow in one direction.
Closet Bend: curved fitting located under the toilet connecting it to the drain.
Closet Flange: ring used to anchor a toilet and connects to the closet bend; sometimes called a floor flange.
Flow Control Valve: device which can reduce costs and improve efficiency by reducing the water flow to a plumbing fixture.
Gasket: flat rubber or fiber ring used to create a watertight seal between metal fixtures.
Interceptor: device which separates oil and grease from drain systems.
Main: the main pipeline in a supply or drain system to which all branches connect.
Manifold: fitting that connects multiple branches to the main, acting as a distribution point.
O-Ring: round rubber washer used to make valve stems watertight.
Scald Guard: valve that maintains the balance between hot and cold water pressure in your shower by shifting back and forth behind the shower handle in response to sudden pressure drops.
Shutoff Valve: valve under toilet or sink to stop water supply for repairs.
Tee: T-shaped fitting used where three pipes intersect.
Trap: a curved portion of plumbing designed to hold enough water to block, or seal, the section of pipe from gasses, odors, and pests.
Valve Seat: the stationary section of a valve.
Vent: sloped or vertical section of drainpipe designed to allow sewer gasses to escape and be replaced by outdoor air so pressure is not lost during the venting.
Water Hammer Arrestor: device which prevents the banging sound known as water hammer by absorbing the hydraulic shock caused from suddenly cutting the water supply to a fixture.
Wye Fitting: drain fitting which connects two sections of pipe at a 45 degree angle.

Plumbing Tools and Materials

ABS: short for Acrylonitrile Butadiene Styrene, this black plastic pipe is rigid and commonly found in drains, vents, and waste lines.
Auger: flexible rod with a curved end used to pull clogs from a toilet trap.
Blowbag : tool with a nozzle and rubber bladder attached to a hose and inserted into a clogged drain where it swells to fill the pipe and releases water in bursts to force a path through the obstruction.
CPVC : chlorinated polyvinyl-chloride; black PVC pipe treated to withstand high temperatures; often used in water supply systems.
Dope: plumbing lubricant used on pipe threads.
Polybutylene (PB): bendable tubing used in some supply lines for bathroom fixtures.
Polyethylene (PE): flexible pipes often used in supply lines.
PEX: crossed-linked polyethylene; stronger than normal PE.
Plumber’s Putty: putty with dough-like consistency used to seal the joints between fixture settings and metal pieces.
Plunger: AKA “plumber’s helper”; six inch rubber suction cup with a wooden handle commonly used to unclog drains and toilets.
PVC: rigid white pipe made of polyvinyl-chloride plastic; often used for drains and waste or vent pipes.
Snake: thin, flexible cord of spiral-wound metal that fits down a drain and is rotated to dislodge clogs.
Teflon Tape: fluorocarbon polymer tape with non-stick properties that is wrapped around the threads of a pipe to create a tighter joint seal.

Septic System-Specific Components

Absorption Field: seeping field designed to filter and disperse the liquid waste from a septic tank; also referred to as a leach field.
Leach Line: pipes which carry the liquid waste from the septic tank to an absorption/leach field.
Septic Tank: large underground tank used mainly in rural settings where sewers are not available; temporarily stores waste as bacteria and gravity separates it into solids, liquids, and sludge before the liquids drain into an absorption field.

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