Plumbing Terms Glossary
Welcome to our comprehensive Plumbing Glossary, an essential resource tailored specifically for plumbing professionals and companies. Whether you’re an experienced plumber, a new technician, or managing a plumbing business, this glossary is designed to enhance your understanding and streamline communication within the industry. Here, you'll find clear and concise definitions of common terms, tools, fixtures, and technical concepts that are integral to daily operations and specialized projects. By familiarizing yourself with these terms, you can ensure precision in your work, improve client interactions, and stay updated with industry standards. Dive in to expand your knowledge and support your plumbing expertise with our curated collection of essential terminology.
A
ABS (Acrylonitrile Butadiene Styrene): A rigid black plastic piping used for waste, vent, and drain lines.
Absorption Field (Disposal Field, Leach Field): A leeching or seeping field engineered to receive septic tank effluent.
Access Panel: An opening in a wall or ceiling near a fixture that allows access for servicing plumbing or electrical systems.
Activated Carbon: A water treatment medium used for dechlorination, organic chemical reduction, and radon reduction.
Adaptor: A fitting that joins different types of pipes together (e.g., ABS to cast iron).
Aerator: A device attached to a faucet that mixes air into flowing water to control flow and reduce splashing.
Air Admittance Valve: A valve that allows air to enter the pipe to equalize pressure, replacing traditional vents.
Air Check Valve: A device that allows water to pass through but prevents air from bleeding out of the tank.
Anti-Scald Valve: A device used to prevent excessively high water temperatures.
Anti-Siphon: A device that prevents the backflow of liquid into a system.
Angle Stop: A shutoff valve between the water supply and a fixture, used for emergency repairs.
Angular Discharge Tube: A discharge tube that changes the direction of water flow by approximately 90 degrees.
Anode Rod: A sacrificial rod installed in a water heater to protect the tank from corrosion.
B
Back Pressure: Pressure that resists the flow of fluid in a piping system.
Backflow: The reverse flow of water from one system into the main distribution system.
Backflow Preventer (Check Valve): A device that prevents water from flowing backward into the main supply.
Backwater Valve: A valve that prevents sewage from flowing back into the house.
Backup: Overflow of a plumbing fixture due to a drain blockage.
Backwash: The reverse flow of water through a filter to remove trapped particles.
Ball Check Valve: A type of check valve that uses a ball to seal against the flow direction.
Ballcock: A fill valve in a toilet tank controlled by a float mechanism.
Ball Passage: The size of the ball that can pass through a toilet trapway.
Basin: A receptacle for holding water discharge, such as a sink or bathtub.
Basin Wrench: A specialized wrench used to tighten or loosen faucet nuts.
Beehive Strainer: A strainer used in urinals to prevent debris from entering the drain.
Biochemical Oxygen Demand (BOD): A measure of the amount of dissolved oxygen needed by microorganisms to break down organic material in water.
Black Pipe: Lacquer-coated cast iron pipe.
Bleed: To remove excess air from a pipe by opening a valve.
Blowbag (Blowfish): A rubber bladder used to clear obstructions in pipes.
Blowdown: Draining part of a boiler to remove contaminants.
Boiler: A tank where water is heated and turned to steam for power or hot water.
Bonnet: The top portion of a compression valve assembly that holds the valve stem.
Box: The female-threaded end of a pipe.
Brackish Water: A mixture of saltwater and freshwater.
Brine: A strong solution of salt used in water softeners.
Braided Hose: A flexible connecting hose.
Brake Horse Power (BHP): The horsepower consumed by a pump, measured on a dynamometer.
C
Catch Basin: An underground container that collects stormwater runoff.
Cavitation: Damage caused by vapor bubbles in a pump exceeding replacement in the suction line.
Centrifugal Pump: A pump that uses centrifugal force to move water.
Centerset: A faucet style with handles 4 inches apart, center-to-center.
Check Stop (Service Stop): A shut-off valve operated with a screwdriver.
Check Valve: A valve that allows fluid to flow in only one direction.
Cleanout Plug: A plug in a trap or drain pipe for clearing blockages.
Clevis Hanger: A pipe hanger with a swivel yoke supported by an adjustable rod.
Closed System: A water system that prevents thermal expansion from increasing pressure.
Closet (Commode, Water Closet): A synonym for a toilet.
Closet Auger: A flexible rod used to remove clogs from a toilet’s trap.
Closet Bend: Connects the closet flange to the toilet drain.
Closet Flange (Floor Flange): Anchors the closet bend to the floor and secures the toilet.
Cock: A faucet or valve for regulating water flow.
Common Vent: A vertical vent connecting multiple fixture branches.
Compression Fitting: A pipe connection that forms a seal without soldering.
Compression Valve: A valve operated by a threaded stem to control flow.
CPVC (Chlorinated Polyvinyl Chloride): Rigid plastic pipe used in water supply systems.
Culvert: A concrete pipe that passes under roads for drainage.
D
Degree Rise: The temperature increase of water after heating.
Desanco Fitting: A compression adapter connecting brass fittings to PVC pipes.
Diaphragm: A flexible membrane in a valve regulating water flow.
Dielectric: A non-conductor of electricity.
Dip Tube: Sends cold water to the bottom of a water heater tank.
Direct Tap: A clamp allowing a branch line addition to the main water line.
Discharge Tube: Connects a disposer or sump pump to the drain line.
Dishwasher Tailpiece: Adapter connecting a basket strainer to the dishwasher inlet.
Diverter: Valves directing water to various outlets.
Drain Valve: Allows drainage from a water heater.
Dual Element Heater: An electric water heater with two heating elements.
DWV (Drainage, Waste, and Vent): Tubing used for drain, waste, or venting pipes.
E
ECO (Energy Cut Off): Safety device that shuts off power to prevent high temperatures.
EF (Energy Factor): Efficiency rating of a water heater.
Efficiency: Ability of a product to utilize input energy effectively.
Elbow: Pipe fitting that changes the direction of a pipe line.
Energy Guide Label: Label showing estimated annual operating costs of water heaters.
Escutcheon: Decorative cover beneath a faucet handle.
Expansion Tank: Absorbs excess pressure from thermal expansion.
F
Fall/Flow: The slope of a pipe for adequate drainage.
Female Fitting: A fitting that receives another pipe or fitting.
First Hour Delivery (Rating): Hot water delivery capacity of a water heater in the first hour.
Fixture: Plumbing devices that provide or dispose of water (e.g., sinks, toilets).
Flapper Valve (Flush Valve): Valve that allows water to flow from the tank to the bowl in a toilet.
Float Ball: Ball connected to the ballcock that controls water levels in a toilet tank.
Floor Flange (Closet Flange): Connects a toilet to a floor drain.
Flow Control Valve: Reduces water flow to fixtures.
Flow Rate: Measurement of water flow, typically in GPM or GPH.
Flange: Rib or collar that attaches piping sections together.
Flue: Passageway for combustion products.
Flue Baffle: Device to regulate combustion gas flow.
Flue Damper: Minimizes heat loss through the flue.
Flushometer: Automatic shut-off valve for toilets.
Flushometer Tank System: Pressurized toilet flushing system.
Flux: Paste used in soldering to prevent oxidation.
Foam Insulation: Insulation surrounding a water heater tank.
French Drain: Covered ditch with stone or pervious material for drainage.
G
Galvanic Action: Corrosion caused by electrical potential between dissimilar metals.
Gate Diverter: Lever on a tub faucet that activates the diverter valve.
Gate Valve: Valve that controls flow by lifting or lowering a gate.
Globe Valve: Valve with a movable plug and a stationary ring seat.
Grain Capacity: Capacity of resin in water softeners, measured in grains.
Gravity Operated Toilet: Toilet that uses the natural downward pressure of water to flush.
Gray Water: Wastewater from sinks, showers, and bathtubs (excluding toilets).
Guide Arm (Float Arm): Connects the flapper valve to the toilet handle.
H
Head Loss: Pressure of water measured at a specific point.
Heat Trap: Restricts heat loss through water connections.
High-Temperature Limit Stop (Anti-Scald Valve, Pressure Balancing Valve): Prevents water temperature from exceeding safe limits.
Horizontal Branch: Lateral drain pipe from fixtures to the waste stack.
Horizontal Run: Distance water travels within a horizontal pipe.
Hose Bibb (Hose Bib): Outdoor faucet for connecting hoses.
House Trap: U-shaped fitting with cleanout plugs for main drains.
Hubless (No-Hub) Pipe: Cast iron drainage pipe without threading.
Hydronic System: Heating or cooling system using water as a heat-transfer medium.
Hydrostatic Pressure: Gravitational pressure exerted by a liquid.
Hydrostatic Test: Test using liquid under pressure to check pipe integrity.
I
ID (Inside Diameter): The internal measurement of a pipe's diameter.
Indirect Wastes: Waste pipes conveying gray water to fixtures like floor drains.
Instantaneous Water Heater (Tankless Water Heater): Heats water on demand without a storage tank.
In-line Pump: Small pump using centrifugal force to move fluids.
Insert Fittings: Sleeve-like fittings with rings or barbs for connecting flexible tubing.
J
J Bend (Return Bend, P-Trap, U-Bend, S-Trap): Curved pipe preventing sewer gases from entering the home.
Jet: Orifice in a toilet designed to initiate siphon action.
Johnni-bolts (Closet Bolts): Bolts used to secure toilet bowls to the closet flange.
Junction Box: Area where incoming power is connected to a water heater.
K
Kafer Fitting: Cast iron fitting with a threaded hub for connecting pipes.
Knockout Plug: PVC test plug used during pipe installation.
L
Lavatory (Lav): Sink or basin for washing, also known as a restroom fixture.
Leach Field: Porous soil area dispersing effluent from a septic tank.
Leader (Downspout): Pipe draining rainwater from gutters to the ground or sewer.
Lock Nut: Nut used to secure pipe connections.
M
Main Line: Primary water supply or drain system connecting all branches.
Male Threads: External threading on pipes and fittings.
Malleable Fittings: Soft, pliable metal fittings.
Manifold: Distribution fitting connecting multiple branches to the main line.
Micron Rating: Measurement indicating the particle size a filter can remove.
Mixing Valve: Valve that blends hot and cold water to achieve desired temperatures.
Multi-Stage Pump: Pump with multiple impellers for increased pressure or flow.
N
Natural Gas: Fuel used in gas-fired water heaters.
Net Usable BTU: Heat energy transferred into water by a heater.
Nipple: Short, tightly threaded pipe connecting fittings.
Nipple Extractor: Tool for unscrewing pipe sections.
No Hub (Hubless) Connector: Connector for joining hubless pipes without threading.
Nonpotable: Water not suitable for drinking.
O
O-Ring: Rubber gasket creating a watertight seal in fittings.
OD (Outside Diameter): The external measurement of a pipe's diameter.
Oakum: Treated hemp rope used to caulk pipe joints.
One-Piece Toilet: Toilet with the tank and bowl manufactured as a single unit.
Operating Cost: Cost associated with running a water heater over time.
Outlet Sewer: Pipe section connecting the septic tank to the drainage field.
P
Packing: Material used in faucets to prevent leaks.
Packing Nut: Nut that holds the faucet stem and packing material.
Parts Per Million (ppm): Measurement of water contaminants by weight.
PB (Polybutylene): Flexible plastic tubing used in water supply systems.
Peak Hour Demand: Time of highest hot water demand.
Peak Load Period: Period with the greatest system demand.
pH (Potential Hydrogen): Measurement of water acidity or alkalinity.
Pilot: Small burner igniting the main burner in a water heater.
Pipe Dope: Pipe-joint compound used to seal threaded fittings.
Pitch: Downward slope of a drain pipe directing water flow.
Plumb: To make vertical or to test for vertical alignment.
Plumber's Putty: Sealant used between fixtures and drain connections.
Plumbing Tree: Prefabricated set of drain, waste, vent, and supply lines.
Plunger: Tool used to create suction in drains or toilets.
Point Of Use Water Heater: Small water heater for remote locations.
Pop-Up Drain: Drain assembly that closes when the lift rod is activated.
Port: Opening in a burner head for gas or air-gas mixture.
Positive Displacement Pump: Pump moving fluids by trapping a fixed volume.
Pressure Balance Valve: Valve maintaining balance between hot and cold water pressures.
Pressure Reducing Valve (PRV): Valve reducing inlet water pressure to a specified outlet value.
Pressure Tank: Tank used to pump water from a well.
Pressure Tubing: Tubing for conducting pressurized or heated fluids.
Petcock: Small faucet for draining liquids or bleeding air pressure.
PVC (Polyvinyl Chloride): Rigid plastic pipe used in drainage, waste, and vent systems.
Q
Quick Connect: Fitting designed for rapid and secure hose connections.
R
Rated Storage Volume: Total water capacity of a storage tank.
Raw Water: Untreated water.
Reamer: Tool for leveling or removing burrs from valve seats.
Recovery (GPH): Volume of water a heater can heat in one hour.
Recovery Factor (RF): Efficiency rating based on energy input to raise water temperature.
Reducer: Fitting connecting pipes of different sizes.
Reserve Capacity: Additional grain capacity in water softeners.
Return Circulation System: System that circulates tempered water to eliminate waste.
Revent: Pipe venting a fixture trap to the main vent system.
Redox: Measurement of reduction-oxidization potential in water.
Reverse Osmosis: Water treatment method filtering impurities through a semi-permeable membrane.
Reverse Trap Water Closet: Toilet with a siphonic trapway and integral flushing system.
Relief Valve: Valve that releases excess temperature or pressure.
Rim Holes: Small holes around a toilet rim for water flow.
Riser: Vertical pipe connecting fixtures to the main supply or vent.
Rough-In: Installation of plumbing lines before finishing walls or floors.
Rough-In Dimensions: Distance from finished surface to fixture mounting points.
Run: Complete section of pipe from supply to fixture or drain to stack.
S
Saddle Valve: Valve mounted on a pipe to make quick connections for low-demand devices.
Safety Shut Off Valve: Valve that automatically shuts off gas or water to prevent hazards.
Sanitary Fitting: Fittings designed for drain, waste, and vent systems to prevent clogs.
Sanitary Sewer: Drain system carrying wastewater to municipal sewers or septic tanks.
Self-Rimming Sink: Sink without a metal ring, supported by a built-in lip.
Shroud: Decorative cover under a wall-mounted lavatory.
Siphon-Vortex Water Closet: Toilet with a trapway that creates siphonic action.
Sleeve: Pipe passing through a wall for inserting another pipe.
Slip Joint: Pipe connection using compression fittings.
Soil Stack: Largest vertical drain line in a building connecting all branch waste lines.
Solder: Alloy used to create fused joints between metal pipes.
Stack: Vertical main in a drainage system extending multiple stories.
Stand Pipe: Vertical pipe receiving water from a washing machine or supplying fire sprinklers.
Static Lift: Vertical distance between water source and pump discharge.
Stop Valve: Shutoff valve under sinks and toilets for individual fixture control.
Straight Cross: T-fitting connecting four pipes of the same diameter.
Sump: Pit or pool for collecting or storing water.
Sump Pump: Pump that removes accumulated water from a sump pit.
Sweating: Soldering or condensation on pipes or fixtures.
T
T & P Valve (Temperature & Pressure Relief Valve): Valve releasing excess temperature or pressure from a tank.
Tail Pipe: Pipe added below the jet assembly in a weak well application.
Tailpiece: Pipe running between a fixture outlet and the trap.
Tank: Reservoir in fixtures like toilets holding flush water.
Tank Cross: Fitting connecting a shallow well pump to a bladder tank.
Tankless Water Heater: Heats water on demand without storage.
Tap Tee: Cast iron tee with a threaded female inlet.
Tee: T-shaped fitting for creating branch lines.
Temperature Rise: Degree increase needed to achieve desired hot water temperature.
Thermal Expansion: Expansion of water when heated.
Thermocouple: Device generating voltage from temperature differences.
Thermostatic Valve: Valve maintaining consistent water temperature by adjusting hot and cold flow.
Thread Seal Tape (PTFE Tape, Teflon Tape, Plumber's Tape): Tape used to seal pipe threads.
Trap: Curved drain section preventing sewer odors from entering.
Trap Arm: Waste arm portion of a trap.
Trap Dip: U-bend portion of a trap.
Trap Primer: Feeder line adding water to a trap to maintain the seal.
Trap Seal: Water level in a trap preventing sewer gases from entering.
Trapway: Channel connecting a toilet bowl to the waste outlet.
Trip Lever: Flush handle and actuating arm on a toilet tank.
Turbulent Flow: Erratic fluid flow with varying velocity and direction.
U
UL (Underwriters Laboratories): Safety certification organization.
Uni-flex: One-piece stop and riser combination with single supply.
Union: Three-piece fitting allowing pipe disconnection without cutting.
V
Vacuum Breaker: Device preventing backflow of contaminated water into supply systems.
Vacuum Relief Valve (Anti-Siphon): Valve preventing internal vacuum conditions in water heaters.
Valve Seat: Static part of a valve where flow stops when the movable part contacts it.
Vent: Pipe allowing air into a drain system to balance pressure.
Vent Header: Main vent pipe connecting multiple vents to the vent stack.
Vent Stack (Stink Pipe): Pipe releasing sewer gases outside the building.
Vent System: Network of vents ensuring proper air circulation in drainage systems.
Venturi: Tube creating suction through fluid velocity increase.
Viscosity: Fluid resistance to flow.
Vitreous China: Ceramic materials used for bathroom fixtures.
W
Washdown Water Closet: Toilet with a trapway at the front and integral flushing rim.
Waste Arm: Drain extension pipe extending a sink drain into a wall.
Waste & Overflow: Bathtub drain assembly removing overflow and wastewater.
Water Consumption: Total water usage in a home, typically measured in gallons.
Water Hardness: Concentration of calcium and magnesium in water.
Waterway Fitting: Channel connecting water heater to inlet and outlet lines.
Wet Vent: Vent that also serves as a drain.
Widespread: Faucet style with separate spout and handles spaced apart.
WYE: Y-shaped fitting for creating branch lines.
Y
Yearly Cost: Annual operating cost of a water heater.
Yoke: Metal casting holding hot and cold valves and mixing chamber.
Yoke Vent: Pipe connecting soil or waste stack to vent stack to regulate pressure.