Plumbing Glossary

Welcome to the Plumbing Glossary created by T&J Rooter Service, your trusted plumber in Toledo, Ohio. As a leading provider of plumbing and drain cleaning services in Northwest Ohio, we understand that navigating the world of plumbing can be overwhelming, especially when faced with unfamiliar terms and jargon. That’s why we’ve compiled this comprehensive glossary to help homeowners, DIY enthusiasts, and curious individuals better understand the language of plumbing.

In this plumbers glossary, you’ll find a wide range of terms covering everything from basic plumbing concepts to advanced techniques and equipment used in drain cleaning. Whether you’re dealing with a leaky faucet, a clogged drain, or a complex plumbing installation, this dictionary resource of plumbing terms will provide you with the knowledge and terminology you need to communicate effectively with your plumber and make informed decisions about your plumbing needs. So, let’s dive in and explore the fascinating world of plumbing!


Absorption Field (Disposal Field, Leach Field): A series of trenches engineered to receive effluent from the septic tank and disperse it uniformly into natural soil.

Access Panel: An opening in a wall or ceiling near a fixture that provides access for servicing the plumbing/electrical system.

Accessible Design: An approach to designing buildings, homes, and products that are easier to access and use by people with disabilities.

Activated Carbon: A water treatment medium used for dechlorination, organic chemical reduction, and radon reduction.

Adaptor (Adapter): A fitting that joins two different types of pipe together, such as ABS to cast iron or threaded to non-threaded.

ADA-Compliant Device: A device fully compliant with the Americans with Disabilities Act Accessibility Guidelines (ADAAG) when properly installed.

Aerator: A device attached to a faucet that mixes air into the flowing water, controlling the flow to reduce splashing.

Air Admittance Valve: A valve that allows air to enter the pipe to equalize pressure, preserving the seal of water in the fixture trap. It replaces a traditional vent.

Americans with Disabilities Act (ADA): A 1990 federal law prohibiting discrimination against people with disabilities and requiring accessible design in public spaces.

Anaerobic: The ability of some microorganisms to survive without oxygen, such as those that break down waste in a septic system.

Angle Stop: A shutoff valve between the water supply and a plumbing fixture, used to shut off water for emergency repairs.

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

Anode Rod: A sacrificial metal rod installed in a water heater tank to protect it from corrosion.

Anti-Scald Valve (Pressure Balancing Valve, High-Temperature Limit Stop): A mechanism that prevents water temperature from exceeding a pre-set tolerance to reduce scalding risk.

Anti-Siphon: A device preventing liquid backflow into a system, commonly used on sprinkler systems.

Aristocraft Bristone Styrine (ABS): A rigid black plastic pipe used for drainage, waste, and vent lines.

Automatic Compensating Valve: A valve that maintains the selected water temperature by regulating fluctuations in pressure.


Back Pressure: Pressure resisting fluid flow in a piping system.
Backup: The overflow of a plumbing fixture due to drain blockage.
Backflow: The reversal of the normal direction of water or wastewater flow, potentially contaminating potable water.
Backflow Preventer (Check Valve): A device preventing water from flowing back into the main distribution system.
Backwater Valve: A valve preventing disposed sewage from reentering the home through the drain system.
Ball Check Valve: A type of backflow preventer using a ball to seal against a seat and stop reverse flow.
Ball Passage: The size of ball that can pass through a toilet’s trapway.
Ballcock: The fill valve controlling water flow from the supply line into a gravity-operated toilet tank.
Barrier-Free: Products and buildings permitting access by all users, including those in wheelchairs.
Basin: A receptacle for holding water, such as a sink or bathtub.
Basin Wrench: A long-handled wrench with swivel jaws designed to reach and tighten faucet fasteners.
Beehive Strainer: A strainer inserted into a urinal to prevent debris from entering the drain.
Bidet: A plumbing fixture used for washing the genitals and posterior.
Bleed: To drain a pipe of excess air by opening a valve at one end.
Boiler: A sealed tank where water is heated and turned to steam for power or hot water.
Branch: Any secondary part of the drain system, also known as a lateral line.
Branch Vent: A vent connecting with a vent stack.
Brass: An alloy primarily composed of copper and zinc, commonly used in plumbing fixtures and fittings.
British Thermal Unit (BTU): The heat energy required to raise 1 pound of water by 1°F.


Calcium Carbonate: A precipitate that forms in hard water lines, water heaters, and boilers.
Catch Basin: A large underground container that collects stormwater runoff through a grate while catching debris.
Cavitation: A vacuum created when a pump’s discharge capacity exceeds the suction line replacement, potentially damaging the pump.
Check Valve (Backflow Preventer): A valve allowing water to flow in only one direction.
Chloramines: Chemical compounds of chlorine and ammonia used to disinfect municipal water supplies.
Chlorine: A chemical widely used for water disinfection and oxidization, but can form harmful compounds like trihalomethanes.
Circuit Vent (Common Vent): A vertical vent connecting two or more fixture branches on the same level.
Cleanout Plug: A plug in a trap or drain pipe providing access for clearing obstructions.
Closed System: A system in which the incoming cold water supply has a device preventing water expansion when heated.
Closet: A term for a toilet or water closet.
Closet Auger: A flexible rod with a curved end used to remove clogs from a toilet’s built-in trap.
Closet Bend: A curved fitting connecting the closet flange to the toilet drain.
Closet Flange (Floor Flange): A ring that anchors the toilet to the floor and connects to the drain pipe.
Coliform Bacteria: Non-pathogenic microorganisms used to test water for harmful bacteria.
Compression Fitting: A connection where a nut compresses a sleeve or ferrule tightly around a pipe or tube.
Compression Valve: A valve opened or closed by raising or lowering a disc via a threaded stem.
Copper: A basic element used in plumbing pipes and brass alloys for fittings.
CPVC (Chlorinated Polyvinyl Chloride): A rigid plastic pipe used in water supply systems where allowed by code.
Culvert: A pipe-like construction passing under a road to allow drainage.


Desanco Fitting: A type of compression adapter connecting tubular brass fittings to PVC pipe.
Diaphragm: A flexible membrane that regulates water flow and buildup within a valve.
Dielectric: A material that does not conduct direct electric current, used to isolate dissimilar metals and prevent galvanic corrosion.
DIP Tube: A tube inside a water heater that sends cold water to the bottom of the tank.
Direct Tap: A clamp allowing a branch line to be added to the main water line.
Drip Leg (Sediment Trap): A capped section of pipe installed at a low point in a gas line to collect condensation and debris.
Dual Flush: A toilet flushing system offering a choice between a full or reduced flush volume to conserve water.
Dynamometer (Dyno): A device measuring engine torque and rotational speed to calculate power output.
DWV (Drain, Waste, and Vent): A designation for drainage, waste, and venting pipe systems.


Effluent: The liquid waste discharged from a septic tank.
Elbow (Ell): A pipe fitting with two openings that changes the direction of the line, available in various angles.
Energy Factor (EF): An efficiency rating for water heaters based on recovery, stand-by loss, and energy input.
Energy Policy Act of 1992: U.S. legislation that set water efficiency standards, such as a 1.6 gallons per flush maximum for toilets.
Escutcheon: A decorative flange that covers the hole in the wall where a pipe enters.
Expansion Tank: A tank attached to a water heater to absorb excess pressure caused by thermal expansion.


Fall (Flow): The slope or pitch of a pipe for proper drainage.
Female Fitting: A fitting that receives a pipe or male fitting.
Fill Valve: A float-operated valve that controls the water level in a toilet tank.
Fitting: A device designed to control and guide the flow of water or connect pipes, such as faucets, valves, and connectors.
Fixture: A device that provides a water supply and/or drainage, such as sinks, toilets, and tubs.
Flange: A lip or rim used for strengthening or attaching pipes or fittings.
Flapper Valve: The part in a toilet tank that opens to release water and closes to seal the flush valve.
Float Ball: The ball connected to the ballcock that rises and falls with the water level in the tank.
Flushing Cycle: The complete flush cycle of a toilet, from handle activation to refill completion.
Flush Valve: The valve in a toilet tank that releases water into the bowl when flushed.
Flux: A substance applied to metal before soldering or brazing to facilitate bonding


Galvanic Corrosion: Corrosion caused by electric current flowing between two dissimilar metals in an electrolyte.
Gasket: A ring-shaped seal used to prevent leaks between joined pipes or fittings.
Gate Valve: A valve that opens by lifting a round or rectangular gate out of the path of the fluid.
Globe Valve: A valve with a spherical body and a disc that closes against a seat to stop flow.
GPF (Gallons Per Flush): The amount of water used in a single flush of a toilet or urinal.
GPM (Gallons Per Minute): The flow rate of water through a fixture or fitting, measured in gallons.
Gravity-Feed Toilet: A toilet that uses the force of gravity and a siphoning action to flush waste.
Gray Water (Grey Water): Wastewater from sinks, showers, tubs, and washing machines, but not toilets or kitchen sinks.


Hard Water: Water with a high mineral content, usually calcium and magnesium.
Heat Trap: A device used to prevent convection heat loss in a water heater tank.
High-Efficiency Toilet (HET): A toilet that uses significantly less water than a standard toilet while providing equal or superior performance.
Hose Bibb: An outdoor water faucet with male threads to which a hose can be attached.
Hot Water Dispenser: A small appliance or fixture that provides instant hot water for cooking or cleaning.
Hydrostatic Pressure Test: A test that uses water pressure to check for leaks in a plumbing system.


Instantaneous Water Heater: A tankless water heater that provides hot water on demand without storing it.
Insulation: Material used to wrap pipes and water heaters to reduce heat loss and improve efficiency.


Jamb Nut: A thin, flat nut used to lock threaded pipe fittings in place.
Joint: The connection point between two pipes, fittings, or valves.
Junction Box: An enclosure housing electrical connections for a pump or other device.


Key Stop: A type of shut-off valve accessed by a square or triangle shaped “key.”
Kitec: A type of plastic piping used in hot and cold water supply systems that is now known to be prone to failure.


Lagging: Insulation wrapped around pipes, water heaters, and boilers to reduce heat loss.
Lavatory: A bathroom sink.
Lead: A toxic metal historically used in plumbing that can leach into drinking water, now strictly regulated.
Lead-Free: Plumbing components containing no more than 0.2% lead are considered “lead-free” by current standards in the U.S.
Leak Detection: The process of identifying and locating leaks in a plumbing system using various methods such as visual inspection, acoustic listening devices, or pressure testing.
Low-Flow: Plumbing fixtures and fittings designed to use less water than traditional models while still providing adequate performance.


Main: The primary water supply pipe that feeds smaller branch lines.
Manifold: A fitting that connects multiple pipes or valves.
Mechanical Joint: A connection between pipes or fittings using bolts, flanges, or other mechanical fastening devices.
Meter: A device used to measure the volume of water flowing through a pipe.
Mixing Valve: A valve that blends hot and cold water to a desired temperature.
Muriatic Acid: A powerful cleaning agent used to remove mineral buildup or rust stains, also known as hydrochloric acid.


Nipple: A short length of pipe with male threads on both ends.
No-Hub Fitting: A type of pipe fitting used to connect cast iron pipes without a hub or bell.
Nozzle: The end of a pipe or hose that directs the flow of water.


O-Ring: A rubber ring used to create a seal between two surfaces.
Oakum: A plumber’s caulking material made from hemp or jute fibers soaked in tar or pitch.
Offset: A combination of fittings used to route a pipe around an obstacle.
Organic Waste: Waste materials that can be broken down by bacteria, such as food scraps and sewage.


P-Trap: A curved section of drain pipe shaped like the letter “P” that holds water to seal out sewer gases.
Packing Nut: The nut that compresses packing material around the stem of a valve to prevent leaks.
PCWS (Pressure Compensating Water Saving) Aerator: A type of faucet aerator that maintains a constant flow rate regardless of changes in water pressure.
PEX (Cross-Linked Polyethylene): A flexible plastic tubing used for water supply lines and radiant heating systems.
pH: A measure of the acidity or alkalinity of water, with 7 being neutral, lower numbers being more acidic, and higher numbers more alkaline.
Pipe Dope: A sealant used on threaded pipe joints to lubricate and prevent leaks, also known as pipe joint compound.
Pipe Wrench: A wrench with serrated jaws and an adjustable hook jaw for gripping and turning pipes and fittings.
Plumber’s Putty: A soft, pliable sealing compound used to create watertight seals around faucets and drains.
Plumber’s Snake (Drain Auger): A flexible, coiled-wire tool used to remove clogs from drains and pipes.
Plumbing Stack: The main vertical drain pipe that carries waste and vent gases out of the building.
Plumbing Trap: A device used to prevent sewer gases from entering the building through drains.
Polybutylene Pipe (PB): A flexible plastic pipe formerly used for water supply lines that is prone to leaks and no longer approved for use in many areas.
Polyvinyl Chloride (PVC): A rigid plastic pipe used for drain, waste, and vent piping.
Potable Water: Water that is safe for drinking, cooking, and washing.
Pressure Gauge: A device used to measure the pressure of water in a pipe or system.
Pressure Reducing Valve (PRV): A valve used to reduce the pressure of incoming water to a safe level for use in the building.
Pressure Relief Valve (PRV): A safety device used to release excess pressure from a water heater or boiler.
Primer: A solvent used to clean and prepare PVC pipe and fittings for solvent welding.
Pump: A mechanical device used to move water or other fluids through a pipe or system.


Reducer: A fitting used to connect two pipes of different sizes.
Relief Valve: A safety device used to release excess pressure from a system.
Reverse Osmosis (RO): A water filtration method that uses a semipermeable membrane to remove impurities.
Riser: A vertical supply pipe that brings water up from the main to fixtures on upper floors.
Rough-In: The installation of water supply and drain pipes before the finished walls and floors are installed.


S-Trap: A type of trap shaped like the letter “S” commonly used in older plumbing systems.
Saddle Valve: A type of valve used to tap into an existing water line to supply water to a fridge or other appliance.
Sanitary Tee: A fitting used to connect horizontal and vertical drain pipes.
Scale: Mineral deposits that can build up inside pipes and fixtures, restricting water flow and reducing efficiency.
Septic Tank: A watertight container buried underground that collects and partially treats wastewater from a building.
Sewage Ejector Pump: A pump used to lift wastewater from a lower level to the main sewer line.
Sewer Snake: A flexible, motorized cable used to remove clogs from sewer pipes.
Shutoff Valve: A valve used to stop the flow of water to a fixture or appliance.
Sillcock: An outdoor water faucet.
Slip Joint: A type of connection used to join two pipes or fittings together without soldering or gluing.
Slope (Pitch): The angle at which a pipe is installed to allow for proper drainage, measured in inches of drop per linear foot.
Solder: A metal alloy used to join copper pipes and fittings together using heat.
Solenoid Valve: An electrically operated valve used to control the flow of water, gas, or other fluids.
Sump: A pit in the basement floor that collects groundwater and surface runoff, and pumps it away from the building.
Sump Pump: A pump used to remove water from a sump pit


T&P Valve (Temperature and Pressure Relief Valve): A safety device on water heaters that opens to release pressure and prevent tank explosions.
Tap: To cut threads into a pipe or fitting, or to connect a smaller pipe to a larger one.
Tee: A fitting shaped like the letter “T” used to connect pipes in a branch configuration.
Thermostatic Mixing Valve: A valve that automatically adjusts the temperature of water delivered to a fixture by mixing hot and cold water.
Thread: The helical groove on a pipe or fitting that allows it to be screwed together with another threaded component.
Toilet Auger: A specialized plumbing snake designed to remove clogs from toilets.
Trap Primer: A device that automatically adds water to a trap to maintain the water seal and prevent sewer gases from entering the building.
Turbidity: A measure of the cloudiness or haziness of water caused by suspended particles.


Union: A fitting that joins two pipes together and allows them to be disconnected without cutting the pipes.
Universal Waste: Hazardous wastes such as batteries, pesticides, and mercury-containing devices that are regulated separately from other hazardous wastes.


Vacuum Breaker: A device used to prevent backflow of water into the potable water supply.
Valve: A device used to control the flow of water or other fluids through a pipe.
Vent: A pipe that allows air to enter the drainage system and sewer gases to escape, preventing pressure buildup and maintaining proper flow.
Vent Stack: The main vertical vent pipe that connects to the building drain and extends through the roof.
Venturi: A constriction in a pipe that increases the velocity of the fluid flowing through it, creating a pressure differential.
Vitreous China: A smooth, glossy ceramic material used to make toilets, sinks, and other plumbing fixtures.


Washer: A flat, circular ring used to create a seal between two surfaces or to spread the load of a threaded fastener.
Waste and Overflow: The drain assembly in a bathtub that includes the main drain and an overflow drain to prevent the tub from overflowing.
Waste Stack: The portion of a waste pipe extend up through the floors for all stories above the first floor and terminating at the vent stack.
Water Closet: Another term for a flush toilet.
Water Hammer: A banging noise in pipes caused by sudden changes in water pressure, often heard when a valve is quickly closed.
Water Heater: An appliance that heats water for use in sinks, showers, and other fixtures.
Water Meter: A device used to measure the volume of water used in a building, usually owned and maintained by the local water utility.
Water Pressure Regulator: A valve used to reduce the pressure of incoming water to a safe and consistent level.
Water Softener: A device that removes minerals from hard water through an ion exchange process.
Wax Ring: A seal used to create a watertight connection between a toilet and a drain pipe.
Wye: A Y-shaped fitting used to join a branch drain to a main drain.


Yoke: A fitting used to connect a water meter to the water supply pipes.


Zone Valve: A valve used to control the flow of water or steam to a specific area or “zone” in a building, often used in hydronic heating systems.

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