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Plumbing Terms Glossary

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A Valve A manual gas shut-off valve.

ABS Acrylonitrile Butadiene Styrene, a stiff black plastic pipe and fittings used for drain, waste, and vent lines.

Absolute Pressure Atmospheric pressure added to gauge pressure.

Absorption Field A leech field engineered to receive septic tank sewage.

Acrylic Thermoplastic used on the surface of bathtubs and whirlpools. Usually comes in sheets and is combined with fiberglass to create shower walls.

Adaptor A fitting that joins two different types of pipes together.

Adjusting Link An adjustable strap/ bar, which forms a connection between the lift rod of a faucet and the ball lever of the drain

Aerator A device screwed into a faucet spout, which mixes air into running water to control flow and reduce splashing

Air Admittance Valve A mechanical valve used to replace a traditional vent to allow air to enter the waste pipe and equalize pressure. It also preserves the seal of water in the fixture trap.

Air Chamber A vertical, air-filled pipe or spring coil, set above the water line to absorb pressure when water is turned off at the faucet. Used to eliminate water hammer.

Air Gap An air-filled space, which allows contaminated water to discharge freely while preventing the contaminated water from siphoning back into the potable water supply

Air Lock A blockage in the flow of liquid.

Air Volume Control Maintains the air charge in a standard water storage tank. Note: Pre-charged tanks do not require an air volume control.

Alkalinity The measurement of elements in a water supply, which determine alkaline conditions; the measure of its capacity to neutralize acids

Ambient Temperature The average temperature of the atmosphere in the vicinity of an appliance.

Americast A patented process that uses a porcelain surface, an enameling grade steel material and a structural composite backing bonded together to create a sink that is similar to cast iron in durability but weighs considerably less

Angle Seat Wrench Valve seat wrench with a handle that includes a 90 degree bend.

Angle Stop A shutoff valve between the water pipes and a faucet. Usually used to shut off water to a fixture in case of an emergency repair.

Angular Discharge Tube A discharge tube that changes the direction of water flow to approximately 90 degrees.

Anode Rod A rod within a water heater, composed of one or more metals to protect the tank from corrosion; it helps prolong the life of the tank

Anti-clog Suction A whirlpool water recirculating system, which prevents clogging without restricting the water flow

Anti-Siphon Used to prevent the backflow of liquid into a system.

Apron The apron, or skirting, a decorating portion of a bathtub that covers the rough-in area from the floor to the top rim of the tub. It is often sold separately from the tub.

Aquastat A thermostat that is submerged in water.

Aquifer A layer or zone below the surface of the earth which is capable of yielding a significant volume of water. The upper level of the aquifer is called the water table.

Arrow Head A heavy duty auger cable tip.

Auger A flexible rod with a curved end used to access the toilet's built-in trap and remove clogs.


Back Flow The flow of water or other liquids, mixtures, or substances into the distributing pipes of a potable supply of water, from any sources other than its intended source.

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

Back Siphonage The negative pressure that causes backflow.

Backup Overflow of a plumbing fixture due to drain stoppage.

Backwater Valve Sewer line valve that prevents sewage from flowing back into the house.

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 Passage This refers to the size of the ball that can pass through the trapway of a toilet. This also relates to trapway size. In general, the trap size will be 1/8 larger than the maximum size ball that can pass through it.

Ballcock The fill valve that controls the flow of water from the water supply line into a gravity-operated toilet tank. It is controlled by a float mechanism that floats in the tank water. When the toilet is flushed, the float drops and opens the ballcock, releasing water into the tank and/or bowl. As the water in the tank is restored, the float rises and shuts off the ballcock when the tank is full. Also known as a float valve.

Band Clamp A flexible band made of a variety of materials that has a cinching device used to secure pipes.

Basin A circular vessel with sloping or curved sides that holds water for washing. A bathroom lavatory or sink.

Basin Wrench A wrench with a long handle with jaws mounted on a swivel that allows the jaws to reach and handle nuts to fasten faucets to a previously installed sink.

BHP Brake horse power. The actual amount of horsepower being consumed by a pump as measured on a dynamometer.

Black Pipe Carbon steel pipe in which the outer diameter has been lacquered (as opposed to bare or galvanized pipe).

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

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.

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

Blue Goo A term given to a buildup of blue toilet cleanser of the type that hangs inside the toilet tank and gradually distributes blue cleanser into the bowl. Over time, it may actually clog the water jets under the rim of the bowl, impairing flush performance.

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

Building Drain The lowest point in a drainage system where the interior drainage pipes meet and are conveyed it to the sewer.

Bushing A pipe fitting used to join two pipes of different sizes. A bushing is threaded inside and out. Also a cylindrical part used as a lining or guide

Butterfly Valve A valve made of a square, rectangular, or round disk attached to a shaft inside a body of the same shape. Rotating the shaft 90 degrees opens or closes the valve

Bypass Type of shower door that consists of two or more panels running in parallel tracks.


Casing A tubular structure intended to be watertight installed in the excavated or drilled hole to maintain the well opening and to prevent ground water from entering the well.

Cast Iron Very durable and heavy metal made of casting on molds to make fixtures such as sinks, tubs and lavatories, covered with a porcelain enamel coating. Casting is made of a series of alloys primarily of iron, carbon, and silicon.

Celcon Nut Connectors used to hand-tighten faucets to lavatory

Centerset Style of bathroom faucet having combined spout and handles, with handles 4 inches apart, center-to-center. Also a single-handle faucet installed on 4 inches center-to-center faucet holes

Cesspool A lined excavation in the ground which receives the discharges of a drainage system -designed to retain the organic matter and solids, but permitting the liquids to seep through the bottom and sides.

CFM Cubic feet per minute

CFT Hundred feet. A selling unit of measure for pipe.

Check Valve A type of backflow preventer installed in a pipe run that allows water to flow in only one direction.

Circuit Vent Plumbing drainage system vertical vent which is run from the last two traps on a horizontal drain line to the main vent stack of a building drainage system.

Cistern Rainwater storage tank, often underground.

Close Coupled Toilet Toilet with a separate tank and bowl, secured to each other, and with a separate tank cover. Also known as a 2-piece toilet

Closed System A system where the incoming cold water supply has a device that will not allow water to expand when heated. (i.e. check valve, backflow preventer, pressure reducing valve, etc.)

Cock A faucet or valve for regulating the flow of water.

Combined Sewer A sewer system that carries both sanitary waste and storm water runoff.

Compression Fitting A kind of tubing or pipe connection where a nut, and then 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. Also a flexible connector that has a nut and gasket designed to attach directly to an SAE standard compression thread, without the use of a sleeve or ferrule.

Compression Valve A type of valve that is often used for water faucets. It is opened or closed by raising or lowering a horizontal disk by a threaded stem.

Concealed Arm Carrier One of a variety of common mechanisms to securely mount a wall-mount lavatory. Unlike a hanger which only supports the lavatory where it meets the wall, the carrier has long arms onto which the lavatory slides

Continuous Hinge Door A shower door that has a full-length continuous metal hinge on the side of the door.

Conventional Vent Atmospheric venting that utilizes the natural convective rise of hot flue gases through the system to release the products of combustion.

Corrosive Water A water condition of low pH (acid condition) that can corrode metal pipes, pool fixtures and pumps. (Unbalanced water)

Cross-connection Any connection or situation that may allow wastewater to enter the supply system.

Crown-vented Trap An air admittance valve attached to a drainpipe, protected by a check valve, designed to equalize pressure in the drain line and to protect the trap seal.

Curtain Drain A ditch sometimes filled with gravel or drainage tile which diverts storm water away from a structure

Cycle Time The amount of time it takes a toilet to complete it's flush cycle, from the instant it is flushed until the water supply shuts off


Dam The barrier built into a trapway of a toilet that controls the water level in the toilet bowl.

Deck Mount Describes a faucet that is mounted on the deck of the bathtub enclosure, rather than on the rim of the bathtub or on the wall. Also referred to as a Roman spout faucet. Also known as a sunken tub, the deck-mount tub is usually mounted on a platform and has no apron or decorative side.

Degree Rise Difference between the starting water temperature and the ending temperature after heating is complete.

Desanco Fitting A type of compression adapter that connects tubular brass fittings to pvc pipe

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

Discharge Head Difference in elevation between the liquid level of the discharge tank and the centerline of the pump. Also includes any additional pressure head that may be present at the discharge tank fluid surface.

Discharge Tube Outlet tube that connects a disposer or sump pump to the drain line.

Disposal Field A series of trenches conveying the sewage from the septic tank laid in such a manner that the flow will be distributed with reasonable uniformity into natural soil.

Diverter Valves which direct water to various outlets. They are used in showers, tub & shower combinations, bidets, Roman tub fillers and kitchen faucet sprayers.

Double Suction Pump A pump where the rotor is suspended between two bearings with the fluid entering on either side of the impeller. Used at higher capacities.

Double Threshold A shower base used in a corner application where one threshold is used as an entrance and the other has a glass wall.

Double Wye Fixture A fitting that has branches coming in at an angle from each side of the main to join the main run.

Drain Any pipe that carries wastewater or water-borne waste.

Drain Seal Gasket Gasket used to seal a drain to a sink to prevent leaks.

Drain Valve Device designed to allow drainage of stored contents from a water heater.

Drip Channel A metal channel that is designed to prevent water running down a shower door from dripping onto the floor when the door is opened.

Dual Element Heater An electric water heater with an upper and lower elements for heating water.

Duo Valve A twin valve (hot & cold) with a single on/off lever used for washing machine boxes

Duostrainer Sink drain fitting consisting of a strainer body attached to the drain opening and a removable basket. Also called a strainer

DWV Drainage, Waste, and Vent systems, which remove wastewater. Not for drinking water.

Dynamic Pressure The pressure when the water is flowing


Eductor A device utilizing a nozzle and throat, installed in a stream of water to create a partial vacuum to draw air or liquid into the stream; commonly used to draw regeneration chemicals into an ion exchange water treatment system, such a softener or deionizer

Efficiency A product's ability to utilize input energy, expressed as a percentage.

Effluent Septic system liquid waste

Ejector A mechanical device for pumping sewage from below the sewer line.

End Body A faucet valve body configuration in which both the inlet and outlet are at the end of the valve body.

End Drain The side of a tub where the drain is found. When facing a tub, if the drain is on the right, this is a Right-Hand tub (RH). If on the left, it is a Left Hand tub (LH). On whirlpools, the pump is located opposite the drain.

Energy Guide Label Label required by the FTC on water heaters that show 1) an estimated annual cost of operation and 2) how that unit's efficiency compares to all other comparable models.

Escutcheon A decorative metal flange or trim shield beneath a faucet handle that covers the faucet stem and the hole in the fixture or wall.

Expansion Tank A tank designed to absorb excess pressure due to thermal expansion. (e.g. closed system)


Fall/Flow The proper slope or pitch of a pipe for adequate drainage.

Faucet Threads Special thread size for fittings that connect to faucets. A cone seal or gasket is usually included because straight threads will not have a complete seal without a gasket.

Feed Pump A pump that supplies water to a boiler.

Feed Water Water introduced into a boiler during operation. It includes make-up and return condensate.

Female Threads Faucet threads that are in place on the inside of a fitting.

Fill Valve The water valve inside a toilet tank that controls the water supply

Filtration Rate The rate at which the water is traveling through the filter, measured as GPM (gallons per minute) per sq. ft.

Fixture A device that provides a supply of water or its disposal, e.g. sinks, tubs, toilets.

Flapper Flush ball. the moving part of the flush valve that seals the water into the tank or allows water to exit the tank for the flush cycle. The most common replacement part used on conventional toilets

Flapper Valve The part on the bottom of the toilet tank that opens to allow water to flow from the tank into the bowl.

Float Ball Or Valve The floating ball connected to the ballcock inside the tank that rises or falls with changing water levels in the tank, and actuates or shuts off the ballcock as needed

Flood Alarm A battery-powered sensor device designed to sound an audible alarm at the first sign of water. Often placed near sump pumps, toilets and other fixtures that sometimes overflow and cause damage

Flow Control Valve Device designed to reduce water flow to a plumbing fixture. Often used to improve efficiency and reduce operating costs. Also a check valve that prevents flow reversal when heater is turned off.

Flue Baffle A device to deflect, check, or regulate flow through a pipe.

Flume Spout An open spout design that is also referred to as a waterfall spout.

Flushometer Toilet valve that automatically shuts off after it meters a certain amount of water flow.

Flushometer Tank System Toilet flushing system that uses supply water pressure to compress water to provide a pressurized flush as opposed to a gravity flush. Flushometer,The valve located at the bottom of a gravity-operated toilet flush tank which opens when the trip lever is actuated and closes when the tank has drained to the desired level. Usually also contains an overflow tube.

Footprint The area of floor space taken up by a water heater or other appliance.


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 (gage) Device for registering water level, discharge, velocity, pressure, etc. A number that defines the thickness of the sheet used to make steel pipe. The larger the number, the thinner the pipe wall.

GPF Gallons Per Flush used in toilets. Current law requires maximum of 1.6 gpf. Older styles were usually 3.5 gpf

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

Gray Water Waste water from sinks, showers, and bathtubs, but not 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

Ground Joint A joint which consists of pressing two smooth mating surfaces together without a gasket or supplemental sealant

Ground Water Naturally occurring water rising from the water table of the surrounding land

Guide Arm Valve which controls water flow into the toilet tank


Hanger A device used to support pipes

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

Hardness Leakage The presence of a consistent concentration of hardness in the effluent from an ion exchange water softener, often due to high concentrations of hardness or sodium in the water being treated (see Leakage).

Heat Cables Electrically-powered flexible cables that generate heat and may be wrapped around exposed pipes to prevent them from freezing

Heat Trap Restriction of heat loss through water connections to a tank

Horizontal Branch Lateral drain pipes that run from plumbing fixtures to the waste stack in a building or in the soil

Horizontal Run The horizontal distance between the point where fluid enters a pipe and the point at which it leaves

Hose Bib An outside cold water faucet on the side of a structure that has a threaded spout which enables a garden hose to connect

House Trap U-shaped fitting with two adjacent cleanout plugs visible at floor level if main drain runs under floor

Hydronic System of forced hot water


Impeller 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

In-line Pump Small pump which pumps fluid through a line on which it is supported and mounted

Indirect Wastes Waste pipe used to convey gray water by discharging it into a plumbing fixture such as a floor drain

Instantaneous Water Heater A type of water heater that heats water as it flows through a heat exchanger coil

Interceptor Device for separating grease and oil from drainage system. See grease trap

Isolation Mount The four small rubber feet located beneath a whirlpool's pump base, or attached to the pulse canister assemblies, designed to reduce noise and vibration when the whirlpool is running.


J Bend The trap section, with a 180-degree bend, or a multi-piece P-trap. Also called a return bend.

Jacket Usually refers to the heating/ cooling jacket surrounding the stuffing box on some pumps; The outer casing (shell) of a water heater

Jet An orifice or other feature of a toilet that is designed to direct water into the trapway quickly to start the siphon action

Jetport Hydrojet dip tube, which creates turbulence in the tank.

Jetter A sewer and drain cleaning machine that uses high water pressure directed through a hose and nozzle to thoroughly clean the pipe. Also called a water jetter or hydro-jetter

Johnni-bolts Bolts used to mount toilet bowls to the closet flange


Kafer Fitting Cast iron drainage pipe fitting with threaded-on hub used to attach to existing cast iron lines

Knockout Plug PVC test plug

Kollar Kap Styrofoam forms used to protect floor drains while concrete is being poured around them


Lateral Sewage Line A sewage line that connects one sewage pipe with another

Lavatory A fixed bowl or basin with running water and drainage for washing. Bathroom sink.

Leach Field Porous soil area, through which septic tank leach lines run, emptying the treated waste.

Leach Lines Pipes that carry effluent from the septic system out to the leach field

Leader Pipe carrying rainwater to the ground or sewer

Limit Stop Faucet control unit used to adjust maximum water temperature

Lock Nut Nut fitted into a piece of pipe and screwed onto another pipe to join the two pieces

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


Main The primary artery of supply of the water supply or drain system in which all the branches connect. In the case of drains, known as the Main Vent.

Male Fitting Fitting that is inserted into another fitting

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

Meter Tailpiece An adapter connecting a water meter to the water supply line

Mini-widespread A special style of bathroom faucet having separate spout and handles, but small enough to fit 4 inch center-to-center faucet holes.

Minimum Run Time The minimum length of time that the pump should run while refilling the pressure tank

Mixing Valve Mixes hot and cold water to achieve a specified delivery temperature

Monobloc Faucet A single-handle faucet, usually a lever

Multi-stage Pump A pump that has more than one impeller.

Multiport Valve Rotary type backwash valve. Can replace up to 6 regular gate valves. Serves various functions.


Neo Angle Base A shower base designed to allow the shower to fit into a corner using minimal floor space while maintaining an elegant look.

Nipple A short length of pipe threaded on both ends (usually less than 12) 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.

Nonpotable Not suitable for drinking.


O Ring Round rubber washer used to create a watertight seal, chiefly around valve stems

One-piece Toilet A toilet in which the tank and bowl are manufactured as a single vitreous china fixture. One-piece toilets usually have a lower profile than two-piece toilets.

Outlet Sewer Pipe section in a septic system which runs between the septic tank and the drainage field.

Outlet/Discharge The opening through which the water exits the pump.

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. It is usually part of the flush valve. It prevents potential water damage caused by a tank overflow. A constant-running condition alerts the user to a 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.


P & T Relief Valve Pressure and Temperature Relief Valve - Same as T & P.

Packing Fibrous material that is used on faucets to prevent leaks.

Parallel System Two or more identical size heaters piped with water connections, that is, cold water travels equal distance into the inlets of the heaters from a T connection and hot water travels equal distance from the outlet of the heaters to a T connection.

Perforated Pipe Pipe designed to discharge water through small, multiple, closely spaced orifices or nozzles, placed in a segment of its circumference for irrigation purposes

Petcock A small faucet for draining liquids or relieving air pressure

Pilot A small burner used to ignite the main burner

Pitch Downward slope of a drain pipe in the direction of the water flow.

Pivot Door A shower door that rotates on two metal pivots at the top and bottom of the door.

Plug Male threaded fitting which seals the end run of a pipe when fitted into a female threaded fitting.

Plumber's Putty A waterproof putty that is used to seal around sink drains and other plumbing fittings

Plunger A rubber suction cup attached to a wooden dowel handle used to create suction in a drain line or a toilet to push a clog through the line.

Pop-up Assembly The drain mechanism of a faucet installed on a lavatory. The drain stopper pops up and down.

Pop-up Drain Type of drain assembly for lavatory and bath. When a lavatory lift rod or bath overflow plate lever is lifted, the pop-up drain closes so the lavatory or tub retains water

Potable Water suitable for drinking.

Pre-Charged Tank A water storage tank pre-charged with air at factory featuring a vinyl bag to separate water from air which prevents waterlogging. This tank design provides greater drawdown than standard tanks. Pre-charged tanks do not require air volume control.

Pressure Balance Valve Shower mixing valve that automatically maintains balance between incoming hot and cold water supplies by immediately regulating fluctuations in pressure. As a result, temperature remains constant, though the outlet pressure may drop. Also known as an anti-scald valve.

Pressure Reducing Valve A valve that automatically reduces inlet water pressure to a specified value at its outlet under static cold water conditions.

Pressure Regulator A valve that automatically cuts off the flow of a liquid or gas at a certain pressure. Regulators are used to allow high-pressure fluid supply lines or tanks to be reduced to safe and/or usable pressures for various applications.

Pressure Tank Device used to pump water from a well.

Priming Jet Opening in bowl through which tank-supplied water flows, designed to propel waste up into the trapway.

PSI Pounds per square inch.

Pull-out Spray Single-control kitchen faucet which offers a retractable hose and spray head to be used for food preparation and cleaning.

Purged Line A plumbing line in which the faucet has been opened and allowed to run for a specified length of time, usually 1-5 minutes.

PVC A rigid white, gray or cream-colored plastic pipe used in non-pressure systems, such as drainage, waste, and vent systems.


Rated Storage Volume Quantity of water stored in a tank.

Recessed Tub A tub that has a decorative finish on one side only, and surrounded by three walls. The apron, or skirting, may not be included and must be ordered separately. The most popular style.

Recovery The amount of water in gallons that can be heated in one hour.

Reducer A fitting that connects pipes of different sizes together.

Reed Switch A serviceable, magnetic sensing switch that triggers the water flow to stop when the neck jet pillow (with magnet) is removed from the whirlpool.

Refill Tube The tube that directs water from a ballcock into the overflow tube to refill the bowl after a siphon break in order to refill the toilet.

Relief Valve A valve that opens to relieve excess temperature.

Repair Clamp Sleeve type clamp used to repair a split pipe, held in place by bolts.

Return Circulation System Tempered water from or near the point of usage which eliminates waste of hot water used for long runs and adds storage to the system.

Revent Pipe installed specifically to vent a fixture trap. Connects with the vent system above the fixture.

Rigid Pipe Pipe designed to transmit the backfill load to the foundation beneath the pipe. Rigid pipe must be supported on the bottom portion of the pipe.

Rim Holes A series of small holes in the underside of a toilet rim, around the circumference of the bowl. Incoming water flows down into the bowl through these holes, creating a rinse effect or wash over the entire inner surface of the bowl.

Riser A vertical assembly of pipe and fittings that generally distributes water upward. A vertical metal or plastic tube or assembly that connects a faucet to the water supply stop valve. Usually made of copper. Metal Flex Risers are corrugated to facilitate bending. Also a supply line that rises from one story to the next.

Roman Spout Deck-mounted faucet spout.
Roof Drain A drain installed at the low spot in a roof that channels water into a drainpipe to prevent pooling.

Roof Flashing Sheet metal installed at any break in a shingled roofline to prevent leaks. Also around sewer vents, fluepipes

Round Front Bowl Standard shape of the front of a toilet bow, having dimensions of 14 wide by 16 ½ long from center of seat hinge holes to front outside rim edge. (about 2 shorter than an elongated bowl)

Run A complete or secondary section of pipe that extends from supply to fixture or drain to stack.

Running Trap An in-line trap mounted in a horizontal drainpipe, where the inlet and outlet are parallel


Saddle Valve A valve mounted on a pipe run by a clamping device, or saddle tee to provide a water supply for a low-demand device

Sanitary Fitting Fitting that joins the assorted pipes in a drain, waste, and vent system, designed to allow solid material to pass through without clogging.

Scupper Drain, normally located on a roof or deck that allows rain water to drain off

Seamless Pipe Pipe with no weld in the circumference

Seat A fitting inside a faucet body where the base of the valve stem makes contact to control the water flow.

Self-Rimming A style of bathroom sink with a rolled and finished edge.

Self-rimming Sink Sink with no metal ring that has a built-in lip of the same material which supports it in the vanity top.

Series System System where a primary heater preheats water to a given desired general purpose temperature and feeds into another heater.

Shallow Well A well with a pumping head of 25 feet or less, permitting use of a suction pump.

Shower Receptor A one-piece base (floor) unit used as a shower, for example, to catch water and direct it to a center drain.

Shroud Color-matched component under a wall-mount lavatory that covers the drain outlet for aesthetic purposes

Shutoff Valve Most commonly refers to angle stops installed under sinks and toilets, but also valves installed on branch lines and alongside the meter.

Side Cutter A heavy duty auger tip for large diameter pipes

Single Threshold Type of shower base used in a three wall installation with the threshold being the side with the door

Siphon A pipe connecting two canals. A tube or pipe through which water flows over a high point by gravity

Siphon Break The point in a toilet flush cycle when air is re-introduced into the trapway, breaking the siphonic action. This is characterized by the deep gurgling sound heard at the end of a flush.

Siphon-Jet A toilet having a siphonic trapway at the rear of the bowl and an integral flushing rim and jet

Siphon-Vortex A toilet having a trapway at the rear of the bowl integral flushing rim and a water supply system with or without a jet, which does not feed directly into the trap.

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 Pipe which is passed through a wall for the purpose of inserting another pipe through it

Snake A stiff steel cable used to clear drains of obstructions and clogs. Sometimes called a plumber's snake, auger or a Roto-Rooter.

Soft Water Water that has a low calcium and magnesium content

Soil Stack Largest vertical drain line to which all branch waste lines connect. This line carries waste to the sewer line

Spigot The plain end of a cast-iron pipe. The spigot is inserted into the bell end of the next pipe to make a water tight joint

Spline Adapter Device sometimes required to form a mating connection between the splines of a valve stem and the splines inside a faucet handle.

Stack The vertical main in the drain, waste, and vent system, extending one or more stories.

Stand Pipe Open vertical pipe that receives water from a washing machine. Also the vertical pipe run supplying water to a fire sprinkler system; also large vertical pipe into which water is pumped in order to produce a desired pressure; a high vertical pipe or reservoir that is used to secure a uniform pressure in a water-supply system.

Static Pressure The pressure when no water is flowing.

Stem Part of the faucet that holds the handle on one end and the washer on the other.

Stop Valve The shutoff valve under sinks and toilets. Allows water supply to be cut off to one fixture without affecting the water supply to other fixtures.

Storage Tank A tank used to hold a specific volume of water.

Sump A pit or pool for draining, collecting, or storing water. A chamber which provides water to the pump.


T-Bolt The 2 anchor bolts that attach a toilet to the floor. Also known as toilet bolts.

Tailpiece Section of pipe that runs between a fixture outlet and the trap.

Tank Fixture reservoir for flush water. On a conventional toilet, the ballcock, flush valve, and trip lever are installed in the tank. A tank lid closes the top tank opening.

Tank Ball The moving part of the flush valve that seals water in or allows water out of the tank during the flush cycle. Also known as the flapper, flush ball, stopper and seal disk.

Tank Bolts Three bolts that hold together the tank, gasket and bowl of a 2-piece toilet

Tank Cross A double-tee-shaped fitting installed between a shallow well pump and the bladder tank with integrated valve and gauge fittings, and an outlet for a pressure-relief valve

Tankless Water Heater Instantaneous water heater.

Tap Adapter Fitting with one plain end and one threaded female end.

Tap Tee Cast iron tee with a threaded female side inlet

Tap Water Water provided by a water company by way of the home's plumbing system

Tapered Pipe Standard type of threads used on iron pipe and pipe fittings

Tee T-shaped fitting with three openings that allow another pipe to be joined at a 90 degree angle, used to create branch lines.

Tempering Valve A in-line hot/cold mixing valve

Test Plug A rubber plug that is used to seal off sections of pipe to allow testing for leakage

Thermostatic Valve Pressure-balancing shower mixing valve with automatic temperature control. When temperature or pressure fluctuations occur at the water inlets, a thermal actuator adjusts the hot and cold ratio to maintain the original temperature setting.

Threading A helical or spiral ridge on a screw, nut, or bolt.

Thumb Nut To ease installation and to prevent over-tightening this nut was designed to be tightened without tools

Tile-In Installation where the sink is fit flush with tile countertop

Transfer Valve Valve that changes the flow of water from one outlet to another

Trap Curved section of drain line that prevents sewer odors from escaping into the atmosphere. All fixtures that have drains must have a P trap installed. A toilet is the only plumbing fixture with an S trap

Trapway Channel in a toilet that connects the bowl to the waste outlet. It is where the siphonic action takes place. The trapway is measured in terms of the largest diameter ball which can pass through it. Also called the passageway

Trip Arm Horizontal bar that connects to the trip lever and trip chain in a toilet. Part of the flush mechanism

Trip Chain Chain that connects the toilet trip arm and the flapper on the flush valve

Trip Lever Handle attached to the outside of the toilet tank used to initiate the flush


ULF Ultra low flush. Widely used description of 1.6 gpf or less toilets.

Uni-flex One piece stop and riser combination. One-piece supply.

Union Three piece fitting that joins two sections of pipe, but allows them to be disconnected without cutting the pipe. Used primarily with steel pipe; never in a DWV system.

Usable Storage Percentage of hot water that can be drawn from a tank before the temperature drops to a point that it is no longer considered hot.


Vacuum Breaker An anti-siphon device that prevents the backflow of contaminated water into the water supply system.

Valve A device that regulates the flow of water.

Valve Seat The non-moving part of a valve. Water flow is stopped when the moveable portion of the valve comes in contact with the valve seat.

Vanity A cabinet that holds a sink and its plumbing, usually with drawers or shelves under the sink for storage. A bathroom storage cabinet under the wash basin.

Vent A pipe that allows air into a drain system to balance the air pressure, preventing water in the traps from being siphoned off.

Vent Header A vent pipe into which several vents connect. The vent pipe leads to the vent stack and out of the building.

Voral Tube Flexible steel hose used for hand-held shower sprays.


Wall Thickness The thickness of the tubing wall.

Waste & Overflow Drain assembly for a bathtub. The outlet at the top removes the overflow water during tub filling and the drain at the bottom removes wastewater when the tub is drained.

Waste Arm Drain extension pipe, usually to extend a sink drain into a wall.

Water Hammer A loud banging noise caused by the hydraulic shock of suddenly shutting off a water supply, where water moves against the side of containing pipe or vessel.

Water Hammer Arrestor A device installed near a fixture to absorb the hydraulic shock caused by a sudden shutoff of water.

Water Heater Appliances for providing a more-or-less constant supply of hot water.

Water Jetter A drain cleaning machine that relies on high water pressure, directed through a hose ans special nozzles to thoroughly clean the inside of a pipe. Sometimes called a jetter or hydro-jetter.

Water Spot Water surface in the toilet bowl once the flush is completed.

Weak Well Weak well application occurs when the pump lowers the water level in the well faster than the well can replenish itself.

Wet Vent Drain or waste pipe that also acts for one or more fixtures on the same line.

Widespread A style of bathroom faucet having separate spout and handles, usually 8 from center of handle to handle. Some widespread faucets can be set with handles up to 12 apart.


Yoke Usually a brass casting that holds both the hot and cold valves and the mixing chamber for the water. May also refer to an assembly of copper or other metal which serves the same function.

Yoke Vent A pipe connecting upward from a soil or waste stack to a vent stack for the purpose of preventing pressure changes in the stacks.