Not sure what “trap weir” or “GPF” actually means? This glossary breaks down the most common (and confusing) plumbing terms in plain English — so you can make informed decisions, whether you’re unclogging a sink or replacing your toilet.
A–C
ABS (Acrylonitrile Butadiene Styrene)
A black plastic pipe used in drain, waste, and vent lines. Rigid and durable, often found in older plumbing systems
Absorption Field (Leach Field)
The gravel-filled area where septic tank effluent is filtered through soil. Critical for final wastewater treatment in a septic system
Auger
A flexible tool designed to pull clogs out of toilet traps. It goes deeper than a plunger
Bleed
Releasing trapped air from a plumbing line — usually by opening a valve
Blowbag
A hose attachment with a rubber bladder that blasts water into clogged pipes to clear them out
Brass
Plumber slang for faucets and fixtures, regardless of actual material
Branch Drain
A smaller pipe that carries wastewater from a single fixture to the main drain line
CPVC (Chlorinated PVC)
A plastic pipe similar to PVC but safe for hot water. Common in indoor water supply lines
D–G
Dope (Pipe Thread Compound)
A paste used on threaded pipe joints to lubricate and seal them
Effluent
Liquid waste that leaves a septic tank and flows into the absorption field
Fitting
Any connector used to join two pieces of pipe — like elbows, tees, or couplings
Flow Rate
How much water moves through a pipe, measured in gallons per minute (GPM); important for showers, faucets, and irrigation
Gallons per Flush (GPF)
The amount of water a toilet uses per flush; federal law limits new toilets to 1.6 GPF or less
Gray Water
Wastewater from sinks, tubs, and washing machines. Not drinkable but sometimes reused for irrigation
K–P
KiloPascal (kPa)
A metric unit of pressure. 100 kPa = about 15 psi. Household water pressure usually ranges from 40–60 psi
Leach Line
Perforated pipe that carries effluent from the septic tank to the absorption field
Maximum Contaminant Level (MCL)
The highest level of a contaminant allowed in drinking water, as set by the EPA
Non-Ferrous
Any pipe or fitting made without iron — won’t rust. Includes copper, brass, and plastic piping
PEX (Cross-Linked Polyethylene)
A flexible, freeze-resistant pipe used in modern water supply lines. Easier to install than rigid pipes
Plumber’s Putty
A soft, moldable sealant used to make watertight seals under sinks and around drains
Plunger
A rubber suction tool (also known as “plumber’s helper”) used to clear clogs in toilets and drains
Polybutylene (PB)
A flexible pipe once used in water lines. No longer recommended due to a high failure rate
Polyethylene (PE)
Flexible plastic tubing used in supply lines. PEX is a stronger, more common upgrade
Potable
Water that’s safe to drink and use for cooking and bathing
Pressure Head
The water pressure created by gravity in a vertical pipe. Important in multi-story home.
PVC (Polyvinyl Chloride)
A white plastic pipe used for drain, waste, and vent systems. Rigid and commonly used in residential plumbing
R–Z
Riser
A vertical pipe that carries water to upper floors or fixtures
Sediment
Rust, sand, or mineral buildup in pipes or tanks — can reduce flow or damage plumbing if not flushed out
Septic Tank
A large underground tank that holds household waste. Solids settle, liquids drain out, and bacteria break down organic material. Needs pumping every three to five years
Snake
A long, flexible cable used to dislodge clogs in sinks and shower drains
Soil Pipe
A large pipe that carries toilet waste out of the house
Teflon Tape
A thin, non-stick tape wrapped around pipe threads to create a watertight seal
Trap Seal
The water in a P-trap or S-trap that blocks sewer gases from entering your home
Trap Weir
The overflow point inside a trap. Helps maintain the right water level to block odors
Water Hammer
A loud banging in your pipes caused by sudden water stoppage. It’s a pressure surge that can damage plumbing if not addressed.
