Plumbing Glossary

Don't know the difference between PVC & CPVC, or faucet & absortion field? This is the page for you!

Before having a plumber or plumbing contractor come to your home, make sure you are up to date on the plumbing service lingo or jargon of the plumbing industry.

ABS: Acrylonitrile Butadiene Styrene. A black plastic pipe used in plumbing for drains and vents.

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Absorption Field: A leeching or seeping field engineered to receive septic tank effluent.

Adjustable Hot Limit Stop: Restricts hot water output in single control faucets and showers to protect against scalding by limiting the swing to the hot side.

Aerator: A screen-like insert screwed onto a faucet outlet. It mixes air with the flowing water to reduce splashing.

Air Admittance Valve: A plumbing device that replaces a traditional vent to allow air to enter the pipe and equalize pressure, preserving the seal of water in the fixture trap.

Air Gap: In the drainage system, the unobstructed vertical opening between the lowest opening of a waste line and the flood level of the device into which it empties. Its purpose is to prevent backflow contamination.

Auger (or Closet Auger): A bendable rod with curved end used by plumbers to remove clogs from a toilet’s trap.

Back Pressure: Pressure that resists the flow of fluid in a piping system.

Back Flow: When water traveling from one system backs into any part of the main distribution system, usually by siphoning.

Back Flow Preventer: A device to prevent back flow, especially into a potable water supply. Required for sprinkler systems, handheld showers, pullout faucet spouts, and kitchen sprayers.

Backup: Overflow of a plumbing fixture due to drain stoppage.

Baffle: An object placed in an appliance to change the direction of, or slow down the flow of air, gases or water.

Balancing Valve: A water heater valve that controls water flow and balances heat distribution to different locations.

Ball Check Valve: A valve that uses a ball to seal against a seat to stop flow in one direction.

Ball Joint: A spherical assembly in shower heads that allows the head to pivot and rotate.

Ballcock: A valve in the tank of a gravity-operated toilet that controls refilling of the tank. It is connected to a float via a metal arm. After flushing, the toilet refills until the float rises high enough to shut off the valve.

Backflow Preventer: A device that prevents wastewater and other contaminants from flowing into the potable water supply. Generally required for sprinkler systems, hand-held showers installed in bathtubs, faucets with pullout spouts, kitchen sprayers, and the like.

Bidet: A plumbing fixture similar in appearance to a toilet bowl used for personal hygiene. It is floor mounted, usually next to a toilet, and consists of a washing basin, faucet and sprayer.

Blackwater: Waste water from a toilet.

Bleed: To drain a pipe of excess air by opening a valve at the end of the pipe.

Blow Torch: A torch used by plumbers to solder pipes, activated by pressurized fuel and air to generate its flame.

Blowbag: A drain-cleaning device consisting of a rubber bladder with a hose fitting on one end and a nozzle on the other. The device attaches to a water hose and is inserted into a clogged drainpipe. As water is introduced, it expands to grip the pipe, and releases pulsating bursts of water through the nozzle, forcing water through the pipe to clear the obstruction. Also known as a blowfish.

Blowdown: Partial venting or draining, under pressure, of the water side of a boiler to reduce or remove unwanted contaminants. Also the pressure drops after releasing a pressure-relief valve.

Boiler: A sealed tank where water is turned to steam for heating or power.

Boiler Feed: A check valve controlling inlet water flow to a boiler.

Bonnet: The top portion of a compression valve assembly, it holds the valve in place as it is tightened against the valve seat at the other end of the assembly.

Brackish Water: Water containing bacteria between 1,000 and 15,000 ppm of dissolved solids.

Brass: Slang for faucets and fittings regardless of materials used.

Burst Pressure: The internal pressure that will cause a piece of tubing to fail.

Branch Drain: Plumbing fixture drain that leads to the main drain line.

Bushing: A fitting that’s threaded inside and outside that joins pipes of different sizes.

CPVC: Chlorinated polyvinyl chloride. A black plastic pipe that can handle high temperatures. Mostly used in water supply systems.

Cleanout Plug: A plug in a trap or drain pipe that provides access for the purpose of clearing an obstruction.

Closet Bend: A curved waste pipe fitting under a toilet that connects the closet flange to the drain.

Closet Flange: A ring that anchors the toilet to the floor and connects it to the closet bend. Also known as a Floor Flange.

Collar: A galvanized sheet metal restricting device used in conjunction with plastic pipe. Its function is to direct and control the intumescent action of the firestopping material.

Compression Fitting: A kind of tubing or pipe connection where a nut and a sleeve or ferrule is placed over a copper or plastic tube and is compressed tightly around the tube as the nut is tightened forming a positive grip and seal without soldering.

Coupling: A short fitting used to join two pieces of pipe.

Cowl: A short fitting used to join two pieces of pipe.

Dam: A barrier in the trapway of a toilet that controls the water level in the toilet bowl.

Diaphragm: A flexible membrane in a valve that deflects down onto a rigid area of the valve body to regulate water flow from the supply lines. This eliminates the possibility of debris build-up within the valve.

Diffuser: A device used to reduce the velocity and increasing the static pressure of a fluid passing through a system.

Dip Tube: A tube inside the water heater that sends cold water to the bottom of the tank.

Diverter: A faucet valve that redirects water from the tub faucet to the shower head.

Dope: A lubricant used by plumbers on pipe threads.

Drain-Waste-Vent System: A pipe system that drains wastewater from the bathroom and vents the drain system.

Effluent: Septic system liquid waste.

Elbow: A curved fitting, usually 90° or 45°, used to change the direction of a pipe run. Also called an “ell.”

Escutcheon: A decorative metal flange or plate that covers and hides the supply line hole in the fixture or wall.

Fitting: Any part that joins together two sections of pipe. Comes in many shapes, sizes & connection styles. Examples: elbows, couplings, bends, wyes, etc.

Fixture: Anything that accepts or discharges water or wastewater: faucets, sinks, toilets, tubs etc.

Flange: The rim or edge at end of a pipe shaft that aids in connecting it to another pipe or anchoring it to a surface.

Flapper: A rubber flap with ball-like shape in the bottom of a toilet lifts to allow flushing and seals off the tank for refilling. Allows water to flow from the tank into the bowl.

Flex Coupling: A rubber fitting that uses steel band clamps to attach to the pipe ends. Mostly used to join sections of DWV pipe, but also connects PVC to clay or cast iron pipe.

Flow Control Valve: Device designed to reduce water flow to a plumbing fixture. Often used to improve efficiency and reduce operating costs.

Flow Rate: Measurement of water flow through a plumbing system in gallons per minutes (GPM) or gallons per hour (GPH).

Float Ball: A floating device connected to the ballcock inside the toilet tank to activate or shut off the ballcock.

Flux: A jelly-like substance used in soldering copper pipes and fittings. Applied before soldering to aid bonding and prevent oxidation.

Galvanizing: The process of applying a coating of zinc to the finished product to provide corrosion protection. The coating can be applied by hot dipping or electrolytic deposition.

Gasket: Flat device usually made of fiber or rubber used to provide a watertight seal between metal joints.

Gate: A device that controls the flow in a conduit, pipe, or tunnel.

Gate Diverter: The pop-up lever on a tub faucet that activates the diverter valve.

Gauge: The thickness of stainless steel and is commonly used in reference to quality grades on certain types of lavatories and sinks. 10 and 20-gauge stainless steel sinks go through a number of polishing and buffing operations to ensure a beautiful finish.

GPF: Gallons Per Flush. The rate of water flow by which toilets and flush valves are measured and regulated. Current law requires maximum of 1.6 GPF. Older styles were usually 3.5 GPF.

Gravity Operated Toilet: A toilet which relies on the natural downward pressure of water in a toilet tank to flush the toilet effectively.

Gray Water: Waste water from fixtures other than toilets.

Grease Trap: A device that captures grease entering a system before it reaches the sewer lines. Usually used in commercial applications such as restaurants or cafeterias.

Hard Water: Natural water containing impurities in various proportions. Traditional hardness is a measure of calcium, minerals or dissolved solids in a solution, measured in parts per million. Hard water generally ranges from 100 to 250 ppm.

Hanger: A device used to support pipes.

Hose Bibb: An outdoor faucet, also used to supply washing machines.

ID: Inside diameter. Measures the inside width of a pipe.

Impeller: A rotating wheel with vanes found inside a centrifugal pump. As it spins at high speed it draws fluids in and thrusts them under pressure to the discharge outlet.

Interceptor: A device for separating grease and oil from drainage systems.

kPa: A metric unit for pressure. 100 kPa = one atmosphere.

L Tubing:  An industry standard for copper tubing defined by the tube wall thickness and identified by a “blue” strip. Type “L” copper tube wall is approximately 50 percent greater thickness than type “M”.

Leach Lines: Pipes that carry effluent from the septic system out to the leach field, a porous soil area where treated waste is emptied.

Low Consumption Toilet: A class of toilet designed to flush using 1.6 gallons of water or less. Also known as “water-saving” toilets.

M Tubing: An industry standard for copper tubing defined by the tube wall thickness. Identified by a “red” stripe.

Main: The primary artery of the supply or drain system to which all the branches connect. Referred to as the Main Vent in the vent system.

Manifold: A fitting that connects a number of branches to the main; serves as a distribution point.

Mapp Gas: A colorless, flammable gas made by combining liquefied petroleum gas with Methylacetylene-Propadiene. It is a stable, non-toxic fuel used in brazing and soldering.

MCL:  Maximum Contaminant Level. The maximum level of a contaminant allowed in water by federal law.

Metal Fatigue: A breakage of the metal caused by the bending and flexing or the expansion and contraction of a metal part beyond its endurance limit.

Nipple: A short piece of pipe installed between couplings or other fittings.

No-Hub Connector: A connector for no-hub iron pipe consisting of a rubber sleeve and a stainless steel band secured by hose clamps. A variation, a neoprene sleeve with two adjustable steel bands, is used for connecting dissimilar materials, as when connecting new plastic pipe to an existing cast-iron drainpipe.

Non-ferrous: Not containing iron.

Oakum: Loosely woven hemp rope that has been treated with oil or other waterproofing agent; it is used to caulk joints in a bell and spigot pipe and fittings.

Overflow Hood: On a bath drain, the decorative hood concealing the overflow.

Overflow Tube: The vertical tube inside a toilet tank that directs water into the bowl in case the ballcock malfunctions and prevents potential water damage caused by a tank overflow. A constant running condition alerts the user to an overflow problem. On most toilets, the overflow tube also has a refill tube flowing into it, which directs water from the ballcock through the overflow tube to the bowl, after a siphon break.

O-Ring: A rubber washer that is round instead of flat. Used in valve stems to create a watertight seal.

OD: Outside diameter. Measures the outside width of a pipe.

PB: Stands for polybutylene. A bendable plastic tubing most often used to supply water to bathroom fixtures.

PE: Stands for polyethylene. A flexible plastic supply line.

PEX: Stands for cross-linked polyethylene. A flexible plastic supply line that is stronger than PE. In bathrooms, it is used for water supply lines.

Plumber’s Putty: A dough-like putty that seals joints between fixture surfaces and metal pieces, such as the drain.

Plumbing Snake: A thin, flexible length of spiral-wound metal, which is inserted into a drain and rotated to clear anything that is clogged in the pipes.

Plunger: A rubber suction cup approx 6? in diameter attached to a wooden dowel handle used to free drain clogs. Also known as a “plumber’s helper”.

Pop-Up Drain: Remote control drain assembly. Also known as a “trip lever drain” for tubs.

Potable: Water that is suitable for consumption.

Pressure Balance Valve: A shower valve that monitors fluctuations in pressure to maintain balance between hot and cold water so that temperature remains constant.

Pressure Head: Pressure in a plumbing system. The unit of measure which is the vertical force exerted by water at a depth of one foot.

PVC: Polyvinyl-chloride. A rigid white plastic pipe used for bathroom drain, waste and vent pipes.

Reducer: A fitting that allows pipes of different sizes to be joined together.

Relief Valve: A valve that opens to relieve excess temperature and/or pressure in the system.

Return: A plumbing fitting with a 180-degree bend.

Riser: A supply line pipe that rises from one story to the next; also the short vertical pipes that bring water from the branch to the fixture.

Scald Guard: A valve designed to prevent extreme water temperature changes through pressure balance technology. When there is a drop in hot or cold water pressure, the scald-guard valve shifts back and forth behind the shower handle to compensate for the sudden change. This valve maintains a constant water temperature to help give you and your family a safe and enjoyable bathing experience.

Scale: A thin coating or layer, usually calcium on the bottom of a tank or interior parts that may prevent heat transfer.

Sediment: The substance that settles on the bottom of a water tank. Also known as lime.

Septic Tank: A tank used to detain domestic wastes to allow the settling of solids prior to distribution. Septic tanks are used when a sewer line is not available to carry them to a treatment plant.

Shutoff Valve: Valves installed under sinks and toilets used to shut off water supply in the event of a malfunction or repair. Also called an Angle Stop, Straight Stop or Supply Stop.

Siphoning: The suction or pulling effect that takes place in the trapway of a toilet as it is filled with outgoing water and waste.

Sleeve: A pipe which is passed through a wall for the purpose of inserting another pipe through it.

Soft Water: Water that has been treated so that it has low mineral content.

Solder: A metal alloy that is melted to create a fused joint between metal pieces. Also the act of melting solder into the joint.

Soil Pipe: A pipe that carries waste from toilets.

Sweep: A pipe bend fitting used in drains to permit smooth passage of waste.

T&P Valve: Temperature and pressure valve. A valve that opens to release excess pressure and temperature in a system.

Tailpiece: The section of pipe that runs between a fixture outlet and the trap.

Tee: A plumbing fitting in the shape of the letter “T,” used to connect three sections of pipe.

Tee Fitting: A fitting that allows another pipe to be joined at a 90-degree angle.

Teflon Tape: White tape made of fluorocarbon polymer. It has non-stick properties and is wrapped around pipe threads in a joint to create a tight seal.

Trap: A curved section of drain that traps a small portion of water to prevent sewer gases from escaping into the bathroom. “P” traps and “S” traps are the types of traps most commonly found in bathrooms.

Trap Seal: The water in a trap or toilet that prevents sewer gases from escaping back through the drain.

Valve: A device that regulates the flow of water.

Valve Seat: The immovable portion of a valve. Water flow is stopped when the movable portion of the valve comes in contact with the valve seat.

Vent: A vertical or sloping portion of drain pipe that allows sewer gasses to escape from the house into the outdoor air and lets air into the drain system to keep air pressure balanced and prevent water in traps from being siphoned off.

Water Hammer Arrestor: A device installed near a fixture to absorb the hydraulic shock that happens when a fixture’s supply is suddenly shut off, causing water hammer, a loud banging noise in the pipes.

Wet Vent: A pipe that both drains wastewater and vents air into the drains. Connects two or more fixtures.

Wax Ring: A seal located between floor flange and toilet to prevent leakage and fumes.

Wye Fitting: A drain fitting that allows one pipe to be joined to another at a 45-degree angle.