Plumbing Glossary


Absorption Field: A seeping field that is designed for the purpose of receiving a septic tank’s effluent.

Acrylonitrile Butadiene Styrene (ABS): A plastic pipe that is meant to be used in drains and vents.

Adjustable Hot Limit Stop: Device that prevents the control from being turned in the direction of hot water. Therefore, it prevents people from being scalded by limiting how hot the water can get in single control faucets and showers.

Aerator: Similar to a screen, this insert is able to be screwed onto a faucet’s outlet. By combining the air with flowing water, it limits splashing.

Air Admittance Valve: Enables air to get into a pipe so pressure is able to be equalized. Able to replace a regular vent, it preserves the seal of water in the fixture trap.

Air Gap: Unobstructed and vertical opening found in a drainage system. Located in the middle of the lowest opening in a waste line and the flood level of the device that it empties into. It does not allow backflow to be contaminated.

Auger: A flexible rod that has a curved end. Clogs found in the traps of toilets are removed with an auger.


Back Pressure: Pressure located in a piping system that is resistant to the water flow.

Back Flow: When water that comes from one particular system backs up into a section that is located in the primary distribution system. Siphoning is a common cause of this issue.

Back Flow Preventer: Back flow is prevented by using this mechanism. This is particularly effective in potable water supplies. These are required in all handheld showers, pullout faucet spouts, sprinkler systems and kitchen sprayers.

Backup: When an overflow results from a drain being clogged.

Baffle: An object that is used to change the direction, or slow down the flow of air, gasses and water when they are diverted into an appliance.

Balancing Valve: A water heater valve that is able to keep the distribution of heat balanced and keep the flow of water under control to different locations.

Ball Check Valve: A valve that prevents flow in one direction by the use of a ball seal that is pressed against the seat.

Ball Joint: A sphere-shaped assembly that is found in a shower. Pivoting and rotation of the head is possible because of the ball joint.

Ballcock: This valve controls tank refilling in a toilet that is operated by gravity. An arm made of plastic or metal is attached to the float. When the toilet has been flushed, filling of the tank will continue until the float rises high enough to enable the valve to be turned off.

Bidet: Looks similar to a standard toilet. This is a plumbing fixture that is designed for the purpose of personal hygiene. A faucet, basin and sprayer are included with a bidet.

Bleed: Bleeding a valve consists of opening it at a pipe’s end and draining all of the excess air out of it.

Blowbag: This is also referred to as a blowfish. A drain cleaning device that is constructed of a rubber bladder with a hose attached to one end and a nozzle attached to the other end. A water hose is then connected to the blowbag and it is positioned inside a clogged drainpipe. The blowbag expands as water flows through it, causing it to firmly grip the pipe. The nozzle shoots out blasts of water which forces it through the pipe, removing the debris that is causing the clog.

Blowdown: When a boiler’s water side is partially vented or drained. The purpose of this is to reduce or remove the contaminants that are present.

Boiler: A tank that has been sealed with the purpose of transforming water into steam. Heat or power are then created from the steam.

Bonnet: The upper portion of a compression valve assembly. The bonnet holds the valve securely in place as it gets tightened against the seat of a valve that can be found on the other end of the assembly.

Brackish Water: When 1,000 to 15,000 ppm of dissolved solids is the amount of bacteria found in a body of water.

Burst Pressure: The internal water pressure that is required to cause a piece of tubing to fail and burst apart.

Branch Drain: A fixture for drain plumbing that links up to the drain line that is primary.

Bushing: A fitting that is used to link pipes of various sizes by threading that can be found on the outside and inside.


Cleanout Plug: A plug that can be found in either a trap or drain pipe that enables a person to remove debris that is causing a blockage.

Closet Bend: A curved fitting that is typically used on waste pipes. The closet flange is connected to the drain with a closet bend.

Closet Flange: Sometimes referred to as a floor flange. A ring that secures a toilet to the floor. The closet bend is connected to the closet flange.

Compression Fitting: Tubing or pipe are connected with this. A copper or plastic tube has a sleeve or ferrule and a nut placed over it. As the nut gets tightened, it becomes compressed very tightly around the tube. A positive seal and grip are formed without the need for any soldering.

Coupling: A short fitting that is made to join two pieces of pipe together.


Dam: A barrier that can be found inside the trapway of a toilet that is in control of the level of water in a toilet bowl.

Diaphragm: A membrane that is flexible and can be found inside a valve. Its purpose is to regulate water that flows from supply lines. It does this by deflecting it down onto an area that is rigid on the valve body. Because of this, no debris will build up inside the valve.

Diffuser: A device that lowers the velocity and raises the static pressure of fluids that pass through a system.

Dip Tube: A tube that water travels through on its way to the bottom of the tank of a water heater.

Diverter: A faucet valve that forces water to flow up to the shower head from the tub faucet.

Dope: A lubricant that is typically used by plumbers on pipe thread.

Drain-Waste-Vent-System: A pipe system that is used to provide drainage for wastewater and vent the drain system in a bathroom.


Effluent: Waste that is liquid and found in a septic system.

Elbow: A curved fitting that is usually at a 90 or 45 degree angle. It is used to change the direction of a pipe run.


Fitting: Refers to any part that is used to connect together two sections of pipe, such as couplings, bends and elbows.

Fixture: Anything that is used for the discharge or acceptance of clean water or wastewater, such as sinks, tubs, faucets and toilets.

Flange: The rim or edge that is located at the end of a pipe shaft that is used when two different types of pipe need to be connected. It can also help to anchor a pipe to a surface.

Flapper: A flap that is manufactured from rubber that has a ball attached at its end. It is found on a toilet tank’s bottom. When the flapper is lifted, a seal is broken and water pours out of the tank to flush the toilet. When the flapper is lowered back into position, the seal is closed and the tank refills with water. It allows for water to flow to the bowl from the tank.

Flex Coupling: A rubber fitting that features band clamps made from metal that attach to the end of pipes. These are typically used for DWV pipe section connections. However, it is also capable of connecting clay pipe or cast iron to PVC.

Flow Control Valve: A device that is used to decrease the volume of water that is allowed to flow in the direction of a plumbing fixture. It is commonly implemented to raise productivity and to make operating expenses go down.

Flow Rate: The measurement of how much water flows through a plumbing system using gallons per minute (GPM) or gallons per hour (GPH).

Float Ball: A device that is connected to the ballcock inside the tank of a toilet and floats in the water. It can turn the ballcock on and off.

Flushometer: Toilet valve that automatically shuts off after a certain amount of water enters the toilet. Most of the time, these can be found in toilets that are in businesses. There are not typically for residential use.

Flux: A substance that is like jelly. It is used in the soldering process for copper fittings and pipes. In order to stop oxidation from happening, the flux is applied before the soldering takes place. This also aids in the process of bonding.


Gallons Per Flush (GPF): The rate of water flow that measures and regulates toilets and flush valves. A law is now in place that makes it illegal for a toilet to have over a 1.6 GPF. Toilets from past years could go as high as a 3.5 GPF.

Galvanizing: In order to prevent corrosion, a zinc coating is applied to items that need to be protected. In order to apply the coating, both hot dipping and electrolytic deposition methods can be used.

Gasket: A device constructed of fiber or rubber that is flat. It helps to create a seal that is watertight between metal joints.

Gate: A device that enables the flow of water in a pipe, tunnel or conduit to be controlled.

Gate Diverter: A lever that raises up on a tub faucet that enables the activation of the diverter valve.

Gauge: A thickness used to measure stainless steel that is commonly used in regards to the level of quality of certain types of lavatories and sinks. Multiple polishing and buffing sessions are performed on 10 and 20-gauge stainless steel sinks to be certain that they are perfect.

Gravity Operated Toilet: A toilet that flushes by utilizing the natural downward pressure of the water.

Gray Water: All waste water that comes from fixtures other than toilets.

Grease Trap: This device is used to catch grease when it first enters a water system. This is before the grease goes into the sewer lines. Restaurants and cafeterias typically employ grease traps.


Hard Water: Natural water containing impurities of various levels. Minerals, dissolved solids and calcium are measured by using traditional hardness. This is done in a solution that is measured in parts per million. 100 to 250 ppm is the standard range for hard water.

Hanger: A device that is used for supporting pipes.

Horizontal Branch: Lateral drain pipes that start at the plumbing fixtures and go all the way to a waste stack that can be placed in a building or in the soil.

Horizontal Run: The horizontal distance from where a fluid enters a pipe and where in goes out.

Hose Bib: A faucet that is located outside. These are often used to bring water into a washing machine.


Impeller: A rotating wheel that contains vanes. It can be found at a centrifugal pump’s interior. Fluids are sucked in and guided to the outlet where they are expelled under pressure while the wheel spins very quickly.

Inside Diameter (ID): The measurement that is used for the inside of a pipe.

Instantaneous Water Heater: A water heater that heats water as it is flowing through a heat exchanger’s coil.


kPa: One atmosphere = 100 kPa. A pressure metric unit.


L Tubing: An industry standard for copper tubing that the thickness of the tube defines. A blue stripe identifies it. Type L copper tube is 50 percent thicker than its type M counterpart.

Leach Lines: Pipes used for the purpose of carrying effluent from a septic system to a leach field, which is an area that is porous and made of soil where treated waste is disposed of.

Low Consumption Toilet: This is also referred to as a water-saving toilet. It is a toilet that is specifically designed to use no more than 1.6 gallons of water for each flush.


M Tubing: An industry standard for copper tubing that the thickness of the tube wall defines. A red stripe identifies it.

Main: An artery of a drain system that is the primary one. It is connected to every branch. This is referred to as the main vent in a vent system.

Manifold: A fitting that connects several branches to the main. This can also be a point of distribution.

Mapp Gas: A colorless and flammable gas. It is created from liquefied petroleum gas that has been mixed with Methlacetylene-Propadiene. It is a fuel that is both stable and non-toxic. Mapp gas is used in the brazing and soldering processes.

Maximum Contaminant Level (MCL): The maximum amount of contaminants that are legally allowed to be in water according to federal law.

Metal Fatigue: Refers to the process of metal breaking after reaching its maximum stress limit due to flexing, contraction, bending or expansion.


Nipple: A short pipe that is placed in between couplings or other types of fittings.

No-Hub Connector: A connector that is used in tandem with a no-hub iron pipe. It is constructed from hose clamps and a sleeve made of rubber attached to a band of stainless steel. Another version exists that is constructed from two adjustable bands of steel and a neoprene sleeve. The main purpose is to join together materials that are not the same. For example, when a pipe made of plastic needs to be connected to a cast-iron pipe.

Non-ferrous: No iron is contained in the item.


Oakum: Rope that is made from loosely woven hemp. It is frequently treated with a waterproofing solution. It is used for caulking joints that are found in bell and spigot pipes. It also can be used to caulk fittings.

Overflow Hood: This hood is a covering for a bath drain’s overflow.

Overflow Tube: A vertical tube that can be found in a toilet tank. It directs the water flow into the bowl in case the ballcock does not work properly. It eliminates the possibility of damage resulting for an overflow of the toilet tank. The water running constantly will alert any person nearby that an overflow might happen. Most toilets made today contain a refill tube that flows into an overflow tube. This directs all of the water from the ballcock through the overflow tube and directly down into the bowl of the toilet. This happens after a siphon break.

O-Ring: A washer that is round and made from rubber. In valve stems, O-rings are used to create watertight seals.

Outside Diameter (OD): This is used to measure the width for the outside of a pipe.


Pitch: The downward angle of a drain pipe that is angled towards water that is flowing.

Plumber’s Putty: A putty that plumber’s use to help them seal various joints found in the center of fixture surfaces and metal pieces.

Plumbing Snake: A long metal piece that is twisted like a spiral. It is both thin and flexible. After the snake has been placed in a toilet or drain that has been clogged, it is constantly twisted around until the cause of the clog has been eliminated.

Plunger: Also referred to as a plumber’s helper. A rubber suction cup attached to a wooden handle. When moved up and down repeatedly, the suction from the plunger removes clogs from pipes and drains.

Polybutylene (PB): Tubing constructed from plastic that is bendable. Used in bathrooms to guide the flow of water to fixtures.

Polyethylene (PE): Flexible plastic that is used to make a supply line.

Cross-linked Polyethylene (PEX): A supply line that is constructed from flexible plastic that is stronger than PE. Bathroom supply lines are frequently made from this.

Polyvinyl-Chloride (PVC): A pipe that is constructed out of rigid plastic. Drain pipes for bathrooms, waste pipes and vents often use this pipe.

Pop-Up Drain: This is also referred to as a trip lever drain. A drain assembly that is operated by remote control.

Potable: Water that has been deemed to be safe for human consumption.

Power Flush System: A system where water that is compressed is used to flush a toilet. It provides a pressurized flush as opposed to a flush generated by the force of gravity. This type of flushing system is usually only employed in businesses or commercial buildings.

Pressure Balance Valve: A shower valve that is designed to keep track of fluctuations in pressure so there is a balance that is maintained between the hot and cold water. This allows the temperature of the water to stay constant.

Pressure Head: Pressure in a plumbing system. A unit of measure that is the same as the force of water that is one foot deep exerts vertically.

Pressure Reducing Valve (PRV): A valve that is connected to the main water line in a residential home. Water that comes into the body of the valve is constricted. This causes the pressure of the water coming into the house to be lowered. High pressure is used by the water company to transport the water. This valve makes the pressure low enough so it is able to be safely used in a home with no fixture damage.


Rated Storage Volume: The amount of water that a tank is holding.

Reducer: A fitting that allows pipes of varying sizes to be connected together.

Relief Valve: A valve than is able to be opened in the event that a system requires the removal of excess temperature and/or pressure.

Return: A fitting that contains a 180-degree bend in it.

Rim Holes: Small holes that are located underneath a toilet rim and around the complete bowl. As soon as the handle has been pushed down to flush the toilet, water begins to flow out of the rim holes. The water rinses debris off of the inner surface of the toilet bowl.

Riser: A pipe that goes between the stories of a building and is used for a supply line. It is a short and vertical pipe that carries water from a branch pipe to a fixture.


Saddle Valve: A valve that is attached to a pipe with the use of a clamping device. This can also refer to a fitting that goes through a pipe’s side. Its purpose is to connect a device with a water demand that is low to an existing line to provide water to the device.

Scald Guard: A valve that is designed to eliminate any changes that are extreme in the water temperature via the means of pressure balance technology. When the pressure of hot or cold water drops, a scald guard immediately begins to move from one side to the other behind the shower’s handle. This helps to compensate for the extreme change in pressure. This valve enables the temperature to constantly be maintained at the same level. People can then take a shower without worrying if they are going to get burned.

Scale: A coating layer that is thin. It is normally located on the inside parts that are stopping calcium or heat from being transferred on the bottom of a tank.

Sediment: Also referred to as lime. A substance that can be found on the bottom of a water tank.

Septic Tank: A tank where waste material is stored until it can be properly disposed of. They are often found in rural areas because there are no sewer lines in the area to take the waste to a treatment plant.

Shutoff Valve: Sometimes called a Straight Stop, Angle Stop or a Supply Stop. This is a valve that is located on the bottom of sinks and toilets. In the event that a sink or toilet requires maintenance of any kind, the shutoff valve will shut off the flow of water to the fixture.

Siphoning: The suction or pulling effect that happens in the trapway of a toilet when it becomes filled with outgoing water and waste.

Sleeve: A pipe that is placed in a wall for the purpose of have another pipe placed through it.

Soft Water: Water that has gone through the treatment process and contains a low mineral content.

Solder: A metal alloy that is melted so that it can fuse together a joint that is located between metal pieces. This also refers to the process of melting solder into a joint.

Soil Pipe: A pipe that carries away toilet wastewater.

Sweep: A pipe that enables the smooth passage of waste into drains.


T & P Valve: Temperature and pressure valve. A valve that can be opened in the event that system pressure and temperature that is in excess needs to be released.

Tailpiece: The section of a pipe that is placed in the center of a fixture outlet and a trap.

Tee: A fitting that has a shape like the letter T. It is able to be connected to three different sections of pipe.

Tee Fitting: A fitting that allows the connection of a pipe at a 90-degree angle.

Teflon Tape: A type of tape that contains fluorocarbon polymer. The properties that it contains allow this tape to be non-stick. The creation of a tight seal is made when Teflon tape is wrapped around a pipe’s threads.

Trap: A curved section of a drain. This traps an amount of water with the purpose of preventing sewer gases from entering into a home. Most bathrooms contain either a P trap or an S trap.

Trap Seal: The water located in a trap or toilet that is there to prevent unpleasant sewer gases from seeping into a house from a drain or the opening in a toilet.


Valve: A device designed for the purpose of regulating the flow of water.

Valve Seat: The part of a valve that is unable to be moved. Water flow is prevented when the valve seat comes into contact with the section of a valve that can’t be moved.

Vent: A section of a drain that is vertical or sloping that allows sewer gases to exit the home and go outside.


Water Hammer Arrestor: It is located close to a fixture. It can withstand the impact that frequently occurs when the flow of water to a fixture is stopped quickly. This results is water hammer, which is a loud banging noise that comes from the pipes.

Wet Vent: A pipe that drains wastewater and vents air into the drains. This joins together two or more fixtures.

Wax Ring: A seal that is located in between the floor flange and a toilet that prevents leakage and fumes.

Wye Fitting: A fitting for a drain that allows the joining of a single pipe to another pipe at a 45-degree angle.