A-Z Glossary of Plumbing Terms

Welcome to the A to Z of Plumbing!

Whether you’re completely new to the world of plumbing, or you’re already a seasoned pro. This helpful A-Z plumbing glossary should help clarify any plumbing terminology you may be unsure of.


Apprentice Plumber: An entry level plumber just getting started in the trade. Different states and municipalities have different requirements as to what is required for one to become an apprentice plumber.

Acrylonitrile Butadiene Styrene (ABS): a black plastic pipe and fittings that are used in plumbing for drainage, sewer & waste and venting. Plastic in modern plumbing has replaced using pipes and fittings of iron, steel and lead. Of note is that no solvent cement or primer can completely glue or solvent weld ABS pipes and fittings to PVC plastics. ABS is non-toxic in nature, resistant to cuts and scratches and under normal conditions will not crack chip or peel.

Absorbent: an absorbent is a chemical or physical material that absorbs or draws suspended solids or other contaminates into it or onto its absorbing pores. Activated Carbon or sometimes referred to as Charcoal is one the most commonly used absorbents in the plumbing industry. Also used in increasing water quality by removing impurities when used as a filter component.

Absorption Field: also called a ‘leach field’ or septic ‘drain field’ is a component of a septic system through which liquid effluent moves in pipes throughout the absorption field from the septic tank after biological processing within the tank. Absorption fields are subsurface areas within soil through which liquid waste water leaches and seeps into the soil over a specified area. This leaching through the soil along with bacterial action removes harmful organisms and treats the waste water which is recycled into the groundwater source.

Acid Waste: waste water contaminated with corrosives or acidic liquids that requires neutralization before being allowed to enter municipal sewer systems. Generally, fixtures specifically for acid waste have a connection to what’s called an acid dilution basin which is used to neutralize the acid before the waste water can enter the sewer system.

Acrylic: thermoplastic commonly utilized as a surface material for bathtubs, basin bases, showers and surroundings in plumbing. Acrylic is available in sheets and is generally formed to the shape of a mold for a tub or shower at a factory with fiberglass added as backing to strengthen the material. Preformed shower and tub basin installs are generally constructed of acrylic material.

Access Panels: An access panel is any opening usually with a protective cover that provides access to certain elements of a plumbing system. This access point allows for servicing or repairing the plumbing system when in need of maintenance, upgrades and renovations.

Adaptor: fitting units that are utilized to join two different types of pipes or systems. Can also be a piece which is used to connect threaded pipe with non-threaded piping. Usually referred to as being male or female fittings or male to female adaptor, etc. Made from a variety of materials but most commonly plastic or metal.

ADA: short for the Americans with Disabilities Act. This act provides legal guidelines outlined by government regulation that must be adhered to in certain constructions or remodels. The guidelines are generally to ensure that disabled individuals can access safe and easy to use plumbing systems and can maintain sanitary conditions.

Aerator: fitting installed at the end of plumbing fixtures that facilitates the mixing of air with water. Used to reduce water flow waste or the conservation of water; but also works to reduce water splashing.

Aeration: mixing of flowing water with air to help with releasing any dissolved gasses or odors that may cause an unpleasant smell or taste to a water. Helps with off gassing or the evaporation of the residual chlorine that many municipalities use in treating water for safe drinking.

AGA: Imprinted marking found on many plumbing accessories including pipes and valves. AGA stands for American Gas Association and provides the rating of each component.

Angle Seat Wrench:  valve seat wrench that has a handle with a 90° bend.

API Specs: Short for the American Petroleum Institute specifications

Apron: The apron or skirt of a bathtub is a decorative portion covering the rough-in area from the floor to the top rim of the tub.

Aquastat: an aquastat is a thermostat that operates under water or submerged. Used to detect internal water temperature for control operations of certain devices.

Auger: often referred to as a ‘snake’ a rod-shaped device that is usually made of or a springing material with a cutting or clearing element on the very end. Used to break up and clear drain clogs or ‘snake’ pipes restoring water flow. Also, a device used to drill holes into the ground for the placement of pipes or system access. Can be mechanical or hand driven.

Auto Pilot: an automated gas pilot device that will shut off a devices gas supply if the burners pilot flame is extinguished.

Air Admittance Valve: valve utilized to allow air into a drainage system without use of a vent. The valve opens and equalizes system pressure but will close to prevent sewage odors or gasses from passing through and causing unwanted smells or odors within a space. The most common air admittance valve is called a Studor vent.

Air Chamber: A vertical air-filled pipe or factory-made spring coil that is installed above the waterline in a potable water system. This area absorbs pressure fluctuations within the system when the valves are turned off. Most municipal codes require air chambers on water connection plumbing fixtures.

Air Gap: also called an ‘air break’; open air-filled space between an outlet end of a plumbing device or piping that allows waste water to discharge freely, which prevents contamination from waste water ever siphoning back into the potable water supply or line. This air gap provides protection to the potable water system from cross contamination or fouling.

Ammonia: A colorless gas with a very sharp odor. Ammonia dissolves easily in water and evaporates quickly and is used along with Chlorine by many municipalities to treat water making it safe for drinking.  Chloramines a secondary disinfectant are produced by the mixing of Chlorine and Ammonia and can cause an unpleasant chemical smell and taste to water.

Angle Stop: angle stops, or angle valves are stops that change direction by 90 degrees and are often utilized as ‘emergency stop valves’. These stop valves are installed before the main water supply and allow quick shut off in the case of emergency conditions or to allow repairs to be made.

Anode Rod: Anode bars or rods are sacrificial rods installed at the top of water heat tanks made of metals such as magnesium or aluminum generally with a steel core. The process of electrolysis will cause the anodes or softer metal to corrode before any other exposed metal within the water heater tank. Must be monitored and replaced as once corroded they will allow corrosion to the metals of the system itself eventually causing failure and necessitating water heater replacement.

Anaerobic Bacteria: bacteria which live and grow in the absence of air or oxygen. Bacteria of this type help provide waste break down within a septic system. Can produce foul odors or smells in the plumbing system.

Annealing: A chemical process generally using heating and cooling, often rapid which changes the physical composition of certain materials. In plumbing this process is used to transform strong and unbendable copper into a soft and bendable form that’s more easily shaped and worked with.

ANSI: Short for the American National Standards Institute. ANSI is a nonprofit, non-government organization that creates voluntary health and safety standards for products used across all segments of the U.S.

Aquifer: underground layer of permeable rock that is water-bearing. Can be rock, rock fractures or gravel, sand or silt from which groundwater can be extracted by building a water well. Also referred to as ‘ground water’ and is where water from the septic leach field eventually ends up purified as it travels deep underground.

Automatic compensating valve: valve supplied with both hot and cold-water flow. These valves provide a way of automatically maintaining water temperature for a specific outlet. Automatic compensating valves are very often used to reduce the risk of scalding or burns caused by water that is too hot.


Back Flush: Generally, a temporary reversal of the normal flow of liquids, solids and gas substances into the opposite direction. Sometimes used to try and clear pipes that have clogs in unknown locations or flow issues.

Back Flow: a situation where water travels from one system back into any other lines of the main distribution system, usually caused by siphoning.

Back Flow Prevention: process of preventing the unnatural and irregular flow of liquids, gases and solid substances towards the main public (drinking) water supply. The most common types of back flow prevention devices are called doubled detector check assemblies and RPZ’s.

Back jet: the whirlpool jets on some lounging baths or jacuzzi type tubs.

Back jet Pulse Canister: the water control device that is responsible for back jets pulsing action.

Backwater Valve: the sewer line valve preventing sewage or waste water from flowing back into a home.

Barrier-Free: refers to a space being made for handicap access usually meaning the area is wheelchair accessible. Sometimes a requirement for construction via ADA laws.

Basin: the sink area or sunken area of wash basins or sinks used in kitchens and bathrooms. Or any circular bowl-shaped object which holds water for washing and cleaning of clothes or dishes.

Basin wrench: also called a sink wrench. Plumbing tool utilized in confined spaces to turn fasteners that would be difficult or impossible to reach with a regular wrench.

Basket strainer: a metal or plastic cup shaped device or basket with holes or slots in it that fits inside a drain that strains the incoming waste water flow removing any debris before it enters the pipe system.

Baffle: A screen, metal piece or other object that is placed within a plumbing fixture that is used to change the flow direction or reduce the flow of water or prevent gas travel. Grease separators are one of the most common baffles found in plumbing, these baffles are used to slow down the flow of waste water. This slowing allows any suspended grease and solids within the waste water to cool and rise or float to the top and become trapped for easy removal.

Balancing Valve or Cock: valves with an adjustable gate or partition device that can increase or decrease water flow. Many have self-sealing ports into which thermometers can be inserted to check the temperatures of the liquid flowing within.

Ball Cock: valve through which water enters a tank design toilet. Fills the tank with water and then shuts off the flow when the water reaches a preset height in the tank usually through a float device. Ball cocks are commonly referred to as float valves.

BC: an abbreviation for brushed chrome a finish utilized on some sink faucets and handles or other bath fixtures.

Beehive Strainer: the strainer basket featured in the bottom of urinals that prevent debris from falling into the drain and potentially clogging the piping.

Bends: generic plumbing term used for all types of elbow shaped piping materials.

BIBB: also called a bibcock or hose bibb. A faucet with a neck down shaped nozzle. Generally found outdoors and used to attach hoses.

Bidets: plumbing fixture that is basically a spray faucet that can be found in homes or hospitals that is attached to the toilet and used for the washing of genital areas after defecating or using the bathroom. Often used in place of toilet paper in many areas.

Biodegradable: refers to materials that can be broken down and degraded through biological action and natural processes. Generally, the process of aerobic and anaerobic decomposition. Substances considered biodegradable are sometimes called ‘Green’ to refer to being natural or that they able to be broken down by natural processes. Certain detergents, soaps, human waste and organic matter represent biodegradable substances.

Black Water: the waste water coming from toilets, bidets, or waste drains that flows into sewer pipes.

Bleed: To drain a water or fluid systems piping system of excess air by opening valves and allowing the air to flow out until only water flows free of air or gas bubbles.

Blind Plug: cap or plug found on no-hub piping used to end a drain line. A Blind plug is attached to the end of the piping line by a no-hub coupling.

Block Sensor Mode: a system mode on touch-less faucets occurring when the faucets sensors continually sense an object. This obstruction causes the faucet to stop normal operation and the faucet will appear to be broken or off.

BN: an abbreviation for brushed nickel a finish used on faucets and other bath or sink fixtures.

BOCA CODE: abbreviated reference of the Building Officials Code Administrators International (BOCA).

Boilers: generally, refers to mechanical oil, wood or electric powered furnaces that are used to heat water. Or a sealed tank where water is converted into steam for heating or power purposes.

Boiler Feed: check valve that controls the inlet water flow to a boiler.

Box: refers to the internal or female end of a threaded pipe.

Box Flange: the flange containing an internal threaded female pipe fitting.

Braided Tubing: flexible tubing often made to handle high pressures that is constructed of synthetic materials and encased in a braided cover of threaded steel, stainless steel or plastics. The braiding protects the tubing and prevents kinking, crimping and abrasions while helping with the tubing’s pressure rating.

Brass seats/seals: most plumbing valves use brass for construction especially on the surface area of moving parts. When the moving part contacts the stationary part the flow of water is cut off and stops. Brass seats because of the soft nature of the metal often wear out over time from the friction of contact and must be repaired or replaced.

Braided Supplies – A flexible pressure tubing usually made of synthetic material that is encased in braided threads of steel or stainless steel. The braided covering protects the synthetic tubing from damage due to abrasions and crimping.

Brazing: a process like soldering, used to fill voids in pipe joints with filler material or metal to join or weld pieces of pipes and fittings together. Brazing filler metals often have melting points of above 1,100 degrees Fahrenheit and contain some amount of silver, copper and phosphorus.

Brine: solution of sodium chloride or ‘salt’ that is used in the ion exchange regeneration type water softeners.

BTU: abbreviation for ‘British Thermal Unit’ a unit of measurement that equates to the amount of heat required to raise one pound of water one degree Fahrenheit higher at sea level.

Bubbler: a water fountain that operates through pressing a button on the front or twisting a handle to generate water flow.

Buchan Trap: an obsolete way of providing ventilation to a waste water drain. Consists of an inline trap with an inlet side vent.

Building Drain: the lowest point of a piping’s drainage system where all discharge or waste water flows into the sewer.

Burst pressure: the rated internal pressure at which a pipe or tubing would fail or burst.

Bushing: type of pipe fitting that is utilized to connect and join two pieces of different sized piping. Joining can be accomplished via many methods but the most common is using threaded ends.


Cast Iron Fittings or Pipes: pipes or fittings that are constructed of heavy metal produced through casting molten metal in a form. Generally, a very heavy and strong material made from cast iron. Often replaced with PVC or ABS when in need of replacement for cost, ease and future maintenance.

Calcium Carbonate (CaCO3): white accumulation that forms in water lines, heaters and boilers in areas with hard water. Often referred to as water ‘scale’.

Calcium & Magnesium: two chemical elements when dissolved in water increase the ‘hardness’ of the water. These elements also contribute to the formation of scale and soap scum.

Carbonate Hardness: the hardness rating of a water supply caused by the presence of dissolved calcium & magnesium carbonates and bicarbonates in the water supply.

Ceramic Discs: some valves use ceramic instead of brass for seating material as it is the hardest material that can be utilized. Ceramic discs are unaffected by water temperature so will not expand or contract with heating and cooling and are not subject to abrasion or damage by debris flowing through the piping system.

Chain Wrench: adjustable type wrench which uses a chain for gripping, generally utilized on large pipes.

Chamfer: refers to the degree of beveling on a pipe end. Chamfering is usually done on pipe prior to threading of the pipe.

Check Valves: one-way valves that has a single inlet and outlet allowing liquid to travel in a single direction only. Used to stop or halt liquid flow in case of a pressure drop or reverse in direction flow. Check valves generally function automatically and will slam shut with pressure or flow direction changes preventing further system damage.

Circuit vent system: a system where one common vent is used to for up to a maximum of eight connected fixtures via a horizontal branch drain. Requires design by a professional engineer for proper vent system function.

Clean Out:  module in which a deplete pipe or exhaust gives access to the system for the clearing out an obstacle.

Closet: It generally refers to a “water closet” most commonly a toilet tank.

Closet Bend: curved fitting beneath the toilet that connects the closet flange to the toilets drain.

Closet Flange: the anchoring ring which attaches to the toilets closet bend and secures it to the floor. The tops of the closet bolts which secure the toilet in place are inserted into slots in the closet flange and bolted down.

Coking ‘carbonizing’: process where a reduction of hydrocarbons results in the formation of carbon residue within a device. This residue will interfere with the movement of mechanical seals usually resulting in device failure such as on water pumps.

Combined Sewer: type of sewer system which carries both sanitary waste and storm water runoff together.

Compensated Hardness: value calculated based on a water’s total hardness or the magnesium to calcium ratio and the sodium concentration of a water supply. This value is used to calculate the reductions in hardness or removal capacity caused by these factors in cation exchange water.

Composting Toilet: self-contained toilet unit that uses the natural process of aerobic decomposition or composting to break down feces.

Condensation: the buildup or creation of water vapor that separates from products of combustion via a reduction in the surface temperatures to below the dew point of surrounding air. Often seen on cold water pipes or toilet tanks on very hot and humid days.

Corrosion: disintegration of a metal by electrolysis or electrochemical means, can cause failure to metal plumbing parts or damaged fixtures.

Corrosive Water: acidic water or water with a low pH. Acidic or corrosive water can corrode metal pipes, pool fixtures and pumps causing failure.

CPe: the solvent Chlorinated Polyethylene which is used as a melting agent to form seams in shower pan liners.

CPvC: abbreviation for Chlorinated Polyvinyl Chloride a type of rigid plastic pipe utilized in water supply systems if local coding permits. Able to withstands high temperatures and is available in straight pipe pieces or in rolled stock.

CW: It is an abbreviation for “Cold Water”.

CWP: It is an abbreviation for “Cold Working Pressure”.

Cycle Time: total time which a toilet takes in completing its flushing cycle. From the moment it is flushed till the water flow shuts down again.


DAM: term for the barrier which is built in a trap way of a toilet for controlling the water level in the toilets bowl.

Deep Well: a drilled or dug well that exceeds a depth of 25ft.

Deionization: process of reducing a water to a non-mineral state by passing it over a bed of resins for to filter out minerals and inorganic matter.

Deionized Water: water that has been deionized and is free of inorganic matter.

Dew Point: temperature at which water will condense into a liquid from a vapor or gas form.

Diaphragm: a flexible membrane in a valve that deflects downwards onto a rigid area of the valve to regulate water flow from the supply inlet. This action eliminates debris build up within the valve itself.

Direct Tap: clamping device allowing for a branch line to be drilled and tapped off a main supply line.

Diverter: valve that diverts and directs fluids such as water to different outlets of the plumbing system such as showers, tubs and sinks.

Dope: term for the pasty lubricant that is used on sealing pipe threads prior to making a connection to a thread pipe.

Drain: Refers to any piping or drain that carries waste water, black water or grey water away.

Drain Cleaning Service: electric drain cleaners and sewer jetters are utilized to remove soft or hard obstructions along the entire length of the drain, this is typically done from the drain opening through the main sewer drain to the lateral piping outside the building.

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

Drain Valve: fixture attached to a device used to drain stored contents. Commonly found on and used to drain water heaters.

DWV: It is an abbreviation for Drainage, Waste and Vent systems.

Duo Valve: twin valve system generally with hot & cold that features a single on/off lever that shuts down or turns on flow. Most commonly found in plumbing for washing machines.


ECO: abbreviation for energy cut off. Energy cut offs are a safety device designed to shut power off to the water heater and prevent too high a water temperature.

Effluent: Fluid waste, possibly dangerous, for the most part indicates fluid waste from septic tanks or systems.

Ejector: mechanical device used to pump sewage from below the sewer line.

Elbow: fittings with two openings, that facilitates changing the direction of the plumbing lines, also sometimes referred to as is an “ell”. Elbows can be found in many different angles, including 90°.

Electrolysis: chemical change process occurring when an electric current is passed through a liquid.

Element: the heating element in an electric type water heater.

Elongated: the design shape of some toilet bowls. Elongated design boils are about two inches longer than a standard toilet bowl.

Enamel: A strong glass like amalgamation connected by fusion to the surface of metal installations or fixtures such as cast iron, baths, toilets and sinks.

Energy Guide Rating or Label: labels found on water heaters and other electronic products required by the FTC that show 1) the estimated annual cost of operation and 2) the units efficiency in comparison to other models.


Fall: The proper, slope, slant or pitch of a pipe for sufficient drainage to occur.

Faucet Threads: specialized thread sizing for fittings that connect to faucets. Usually a cone seal or gasket is also included because straight threads will not form a complete seal without the gasket.

Feed Pump: the pump that supplies water to a boiler.

Feed Water: water that is supplied to a boiler during its operation which includes make up and return condensate.   

Female Fitting: fitting that receives a pipe or another fitting inserted into it.

Female Threads:  pipe threads that are in place on the inside of a fitting

Fernco: It usually refers to rubber coupling.

Filter Element: device within a filter that is designed to trap suspended solids or debris as water flows through it. Can be chemical or mechanical in nature.

Filtrate: liquid that has been filtered.

Filtration rate: a rating that describes how much water passes through the filter in a gallons per hour rating.

Finish Plumbing: installation of plumbing fixtures which finishes the install and makes the system operational.

Finished Water: water that has been treated, filtered or purified in some manner and is ready for usage.

First Draw: indicates the first water drawn off a plumbing system from the fixtures that has been sitting in the piping overnight or longer upon first use of the system. If from a lead based pipe system this water would have higher levels of lead contamination from sitting.

Fitting: any pipe part that is utilized to join other sections of piping. Can be elbows, couplings, bushings, etc.

Fixture: device that provides a supply or access to a supply of water.

Flapper Flush Ball: represents the moving part of a flush valve which works to seal the water into the tank or allows the water to flow out when lifted when the toilet is flushed. One of the most common repairs needed to standard toilets.

Flexible or Flex Connector: braided line of hose used to connect faucets, washing machines or toilets to the water supply stop valve. Generally made from stainless steel or PVC/Polyester reinforced hose which provides abrasion and pull resistance.

Float Ball: floating ball with a toilet tank that is connected to the ballcock inside the tank. Rises or falls with the changing water levels in the tank and works to actuate or shut down water flow as needed.

Flocculant: chemical substance used to promote the aggregation or coagulation of suspended particles in a water source.

Floor Drain: drainage fitting that is flush with floor, generally used in basement drains or the floor of showers.

Flow Control Valve: a device used to reduce water flow to a plumbing fixture to improve efficiency and reduce operating costs or for conservation of water.

Flow Rate: a flow rating for a water supply device rated in gallons per minute (GPM) or gallons per hour (GPH).

Flux: special paste that is applied to copper pipes and fittings before soldering that aids in the fusion process and prevents oxidation.

Foam Insulation: insulation used on certain devices such as water heaters that surrounds the surface of the water tank.

FHT: abbreviation for “female hose threads”.

Fiberglass: It is a form of glass transformed into a fibrous form. It is used for making bathtubs, boats, basins etc.

FIP (S): It is an abbreviation for “female iron pipe”.

Friction Loss: term used to describe the loss of pressure that is caused with a plumbing system by the turbulence that is created by the water flowing through the piping.

Frost Line: depth at which frost penetrates the ground during the winter or freezing weather.


Gas Control Device: device used to regulate the gas pressure on a gas water heater.

Gasket: device generally made of fibrous material or rubber that is used to provide a watertight seal between metal joints or other fixtures preventing leakage.

Grab Bar: represents a safety bar installed within a bathtub or shower to provide support while showering or bathing. Sometimes necessary to ensure barrier free compliance in showers, bathes or toilets.

Gravity Operated Toilet: toilet that function using the natural downward pressure of water in a toilet tank to flush.

GPF: It is an abbreviation for “Gallons per Flush” used in toilets.

GPH: It is an abbreviation for “Gallons per Hour” used as rating for a devices water flow capacity.

GPM: It is an abbreviation for “Gallons per Minute”.

Grease Trap: trapping device used to capture grease entering a plumbing system before it reaches the sewer lines. Generally found in commercial operations such as restaurants or cafeterias.

Grey Water: waste water from sinks, drains, showers and baths that hasn’t been exposed to fecal or urine contamination.

Ground Water: naturally occurring water source that is found within the earth.


Hand Shower: It is a shower head with a handle which is designed in a way that it gets connected with a water supply system with a bendable pipe.

Hard Water: water source often natural that contains impurities. Traditional water hardness is a measure of calcium or dissolved solids in a solution, measured in parts per million (ppm). Hard water generally ranges from 100 to 250 ppm concentration levels.

Hardness: represents the concentration level of dissolved minerals in water (calcium and magnesium) being the most common. With the amount measured in grains per gallon (GPG).

Hose Bibb: represents an outdoor fixture or faucet, also used to supply washing machines.

H.P.: It is an abbreviation for “Horse Power”.

H.T.: It is an abbreviation for “Hose Threads”.

HVAC: abbreviation for heating, ventilation, and air conditioning (AC).

H.W.: It is an abbreviation for “Hot Water”.

Hydrolysis: reaction of salts with water that results in the formation of an acid and a base byproduct.

Hydrostatic Pressure: the pressure exerted by or existing within a liquid at rest in a system.

Hydrostatic Test: test that uses a non-compressible liquid under pressure at a level equal to or greater than the max pressure that will be utilized by the system in operation to test the system.


I.D.: It is an abbreviation for “Inside Diameter”, all pipes are sized according to the inside diameter.

Indirect Waste Pipe: a waste pipe that carries gray water and discharges it into a plumbing fixture such as a floor drain.

Injection: drawing of primary air into a gas burner by means of a flow of fuel gas.

In-line Pump: a pump which pumps fluid through a line on which the pump is mounted.

Input: the quantity or amount of fuel that is used by a water heater in a given period of time, the standard is in one hour.

Input Rate: quantity of heat or fuel supplied to an appliance. With the amount expressed in volume of heat units per volume of time generally (BTUs/hour).

Input Rating: rating for the gas burning capacity of an appliance in BTU’s per hour as specified by its manufacturer.

Instantaneous Water Heater: design of water heater that heats water as it flows through a heat exchanger coil.

IPS: It stands for “Iron Pipe Size”. Same as NPS, with standard sized pipe threads.

IPT: It stands for “Iron Pipe Thread”.


JTU: abbreviation for Jackson Turbidity Unit

J Bend: trap section featuring a 180-degree bend, also called a return bend.

J Hook: hanger for pipe support that is in the shape of a ‘J’.

Jacket: the heating or cooling insulation jacket that surrounds the stuffing box on some pumps. Also, the outer shell of a water heater.

Jackson Turbidity Unit: quantitative unit of turbidity based on the comparison of a liquid like water with a suspension of a specify type of silica.

Jet: orifice or feature of a toilet designed to direct water into the trap way very quickly to start the siphon action in motion.

Joint: term for one length of pipe.

Junction Box:  a box for utilities where incoming current is connected in an electrical appliance.


Kilowatt: measurement for the supplied rate of energy or power, equal to 1000 watts or 3412 BTU per hour.

Knockout Plug: PVC test plug.


LDO: abbreviation for lint, dust, and oil

LP: abbreviation for liquid propane which is used as fuel for some gas water heaters.

Lateral Sewage Line: sewage line that connects one sewage pipe with another.

Lavatory:  fixed bowl or basin with running water and drainage for washing. In example a common bathroom sink.

Leach Field: porous soil area where septic tank leach lines run, emptying treated waste for return to the ground water supply.

Leach Lines: pipes that carry effluent or waste water from the septic system out to the leach field.

Leakage: represents loss of fluid usually due to mechanical breakdown, gasket wear, corrosion or cracking damaged to system components.

Lean Mixture: air-gas mixture that contains more air than needed for complete combustion of the gas resulting in inefficiency.

Length: common measure term for a unit of linear measure for pipes, such as 10 or 20 ft.

Lime:  a common contaminate within water supplies and thus system where it builds up to sediment. Can also cause scaling or lime scale but sometimes used to soften water hardness.

Limit Stop: faucet control device which is used to adjust maximum water temperature.

Lock Nut: a nut fitted onto a piece of pipe and screwed onto another pipe to join the two pieces together or lock them.

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

LWCO:  It stands for “Low water cut off”.


M-Tubing: industry standard for copper tubing that’s defined by the tube wall thickness which is identified by a “red” stripe on the pipe.

MC Tank: Acetylene tank holding 10 cu.ft. of gas, used for plumbing.

Macerator:  device installed in a drain line between a toilet and the soil stack to reduce solids to liquid form. Also, commonly a device attached to the bottom on kitchen sink and called a ‘garbage disposal’.

Magnesium: crustal earth element and a contributing compound to naturally occurring hard water.

Main: term referring to the primary supply of water for a system to which all the branches connect. In the case of drains, known as the main vent.

Male Fitting: a plumbing fitting that is inserted into another fitting generally a female fitting to connect the pieces.

Male Threads: represents the threads that occur outside of pipes and fittings that fit into another pipe or fitting piece.

Malleable Fittings: fittings that are made of a soft metal such as cast iron which is more malleable or pliable than other materials which can help with ensuring a snug connection and prevent leaks.

Manganese: Earth element found dissolved in ground water, usually present with dissolved iron but in much lower concentration. Causes black stains and other problems similar to iron. Can be removed by a water softener or it can be precipitated by chlorine at a pH of 9.5 or above.

Manhole: sewer access opening hole, generally covered with a metal grate or heavy metal disc. Provides an access opening so that a person may enter a sewer, boiler, drain, etc.

Mapp Gas: colorless, flammable gas used for heating and low temp welding or fusion. Produced by combining liquified petroleum gas with Methylacetylene-Propadiene. It is a stable, non-toxic fuel used in brazing and soldering.

Mechanical Controls: term for dials, slides, switches, knobs, buttons, that are used to operate devices such as stoves, boilers, water heaters, etc.

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

Meter Tailpiece:  adapter piece that connects a water meter to a water supply line.

MHT: It is an abbreviation for “Male Hose Threads”.

Micron: small unit of measurement, representing one thousandth of a meter. Used to describe filter pore sizes of mechanical type filtration devices.

Mission Coupling: neoprene flex coupling, connecting pvc to pvc or clay to pvc.

Mixer: part of the burner where air and gas are mixed before delivery to the burner ports for combustion.

Mixing Valve: valve that mixes incoming hot and cold water to achieve a specified delivery temperature or to reduce risk of scalding.

MPT: It stands for “Male Pipe Threads”.

Multi-Stage Pump: a pump that has more than one impeller and thus generally has more than one operation speed or functional capacity.

Municipal Water Supply: represents water that is supplied by a city or town for public use, i.e. tap water. Usually held in a reservoir of either a natural of man made type.


Natural Gas:  colorless, odorless fuel derived from the earth. Generally, consists of Methane (CH4). Strong odorants are added to aid in leak detection.

Net Usable BTU: represents the portion of a fuel’s heat energy transferred into the water by a heater.

Nominal: It is used for measuring rough sizes only and doesn’t refer to exact dimensions.

Non-Potable: refers to a water source that is not suitable for drinking.

NPS: It is an abbreviation for “National Pipe Straight Threads Standard”.

NPSM: It stands for “National Pipe Straight Mechanical”.

NPT: NPT stands for “National Pipe Tapered Threads. It is a United States standard for threaded fixtures.


O-Ring: round shaped rubber washer used to create a watertight seal, chiefly around valve stems. Usually creates seal by pressure being applied to the ring thus sealing and preventing leaks.

OD: abbreviation for outside diameter, though not common and not standard sometimes piping will reference the OD.

OEM: abbreviation for the original equipment manufacturer (OEM).

Oil Powered: water heater that uses oil as its fuel source.

One-Piece Toilet: toilet that is manufactured as single piece, generally have a lower profile than two-piece toilets.

Orbital Weld: circumferential, full fusion weld used to connect two lengths of tubing.

Organic Matter: having a plant or animal origin in nature, generally biodegradable.

Orifice: opening through which gas is discharged and gas flow is limited and/or controlled.

Outlet / Discharge: opening through which water exits or discharges from a pump or system.

Outlet Sewer: section of pipe within a septic system which runs between the septic tank and the drainage field.

Ovality: It is an estimated difference between the narrowest OD and the widest OD of a pipe or a tube.


P & T Relief Valve: pressure and temperature relief valve used to relieve pressure or control temperature.

PB: abbreviation for Polybutylene which is a flexible plastic tube used in water supply systems if allowed by code.

PE: Polyethylene plastic material.

PEX: cross-linked polyethylene (PEX). This tubing is commonly used for hydronic radiant floor heat but also water supply lines as it’s stronger than PE.

PoS:    abbreviation for porcelain on steel. A common finish on sinks and bath tubs.

PP: abbreviation for Polypropylene pipe.

PPM:  abbreviation for parts per million, a commonly used measurement for impurities or contaminants in water.

PR: abbreviation for a pressure regulator. Pressure regulators are required in instances where pressure exceeds 80 PSI on potable water supplies inside a structure.

PSI: abbreviation for pounds per square inch a measurement of pressure force.

PVC: abbreviation for polyvinyl Chloride a type of plastic. Generally, comes as rigid white or cream-colored plastic pipe used in non-pressure systems, such as drainage, waste, and vent systems.

Peak Hour Demand: references the time period with the largest demand for hot water usage within a household.

Perforated Pipe: is piping designed to discharge water through small, multiple, or closely spaced orifices or nozzles. Usually placed in circle configuration and used for its irrigation properties in lawn care and gardening.

Petcock: small faucet piece for draining liquids or relieving air pressure.

Phenol: a dangerous, poisonous and carcinogenic chemical often found in municipal water supplies. Also known as carbolic acid, phenol is a benzene derivative.

Pickling: process in which metal piping is immersed into acid bath for removal of scale, oil, dirt, etc.

Pilot: a small burner that is used to ignite the main burner.

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

Plug: male threaded fitting that seals the end run of a pipe when fitted into a female threaded fitting.

Plumber’s Helper: term sometimes used to refer to a standard drain plunger.

Plumber’s Putty: pliable putty substance that is used to seal joints between drain pieces and fixture surfaces.

Plumbing Tree: prefabricated set of drain waste, vent, and supply lines.

Pneumatic: in relation to devices that utilize compressed air for a power source or operation.

Porcelain: a white ceramic ware that consists of quartz, kaolin, and feldspar. Porcelain is fired at a high temperature on steel or cast iron to fuse it and create the surface of some bathtubs and kitchen sinks.

Porcelain Enamel: vitreous enamel. Often refers to pressed steel products with a porcelain glaze.

Porosity: measurement of the volume of internal pores, voids, in ion exchangers and filter media. Sometimes expressed as a ratio to the total volume of the medium.

Port: opening in a burner head through which gas or an air-gas mixture is discharged for ignition.

Potable Water: water source that is suitable for drinking.

Powder-Coating: technique for applying paint to metal items. The metal item is covered with a powder of dry paint particles and is then baked in an oven. This causes the powder to melt and harden into a tough, colorful finish.

Pre-Heated Water: represents water that has been heated before being supplied.

Pressure Loss: term for the loss of pressure that occurs whenever water moves through a pipe or when water moves uphill against the force of gravity.

Pressure Reducing Valve: a valve that is used to reduce inlet water pressure to a specified value.

Pressure Tubing: specialized tubing that is used to carry fluids under pressure or at elevated temperatures and produced to stricter tolerances than pipe.

Purged Line: opening a plumbing line and allowing it to run for a specified length of time, usually 1-5 minutes to clear out the line of any contaminated water or sediment.


Red Water: water which has a reddish or brownish appearance due to the presence of precipitated iron and/or iron bacteria sometimes with noticeable sediment within.

Reducer: fitting which connects piping of different sizes together.

Refill Tube: Refill Tube carries water from the ball cock to the overflow pipe after the siphon order up to refill the lavatory bowl.

Relief Valve: valve that opens to relieve excess temperature or pressure within a system.

Reverse Osmosis: specialized water treatment and purification method where water is forced through a semi permeable membrane which filters out impurities.

Rim Holes: A toilet basin has a rim in which water runs through the installed pipes. The structure possesses the holes, which we call the rim holes.

Riser: A vertical congregation of ducts and fittings that for the most part disseminates water upward.

Residual Chlorine: represents Chlorine remaining in treated water after treatment via a treatment system or municipal plant over a specified period. This residual Chlorine amount and contact time provides continuing protection throughout a distribution system. Can give water an off taste and Chlorine or ‘pool’ smell, which can be resolved through letting the water sit for a time and letting the residual Chlorine or Chloramines off gas.


Safe Drinking Water Protection Act: amendment to the Public Health Service Act, which was passed in 1976 to protect public health by establishing uniform drinking water standards for the United States.

Safety Shutoff Valve: safety device on a gas appliance that shuts off the gas supply to prevent a hazardous situation if the flame or pilot light becomes extinguished.

Sanitary Fitting: It is a kind of fitting that joins various pipes in deplete, waste and vent framework; intended to enable strong material to go through without stopping up.

Scale: thin coating or layer, usually calcium on the bottom of a tank or interior parts that may prevent heat transfer. Also develops on showers and tubs and gives them a hazy look.

Septic Pumping: When a septic tank is emptied, the accumulated sludge is pumped out of the tank by a vacuum truck. How often the septic tank must be emptied depends on the volume of the tank, the ambient temperature, as well as usage, and other system characteristics.

Septic Tank: a watertight chamber made of concrete, fiberglass, or PVC, through which domestic wastewater flows for primary treatment.

Service Entrance: the connecting pipe between the water company piping and the water meter

Sewer: It refers to the drainage which occurs outside any building in the sewers.

Shallow Well: a well with a maximum depth of 25 feet or less.

SDR: It stands for “Standard Dimension ratio”.

Soda Ash: common name for sodium carbonate, Na2CO3 which is a chemical compound sometimes used in soap and detergents to neutralize acid water.

Soft Water: the opposite of hard water. Consisting of water that has a low calcium and magnesium concentration.

Solder: It is a metal alloy which is melted in order to join with other metal surfaces.

Solute: substance which is dissolved in and by a solvent. Dissolved solids, such as the minerals found in water, are solutes.

Solvent Weld: the fastening together of any of the types of PVC pipe and fittings with solvent-based cement.

Static Pressure: It refers to a kind of pressure when no water is flowing through the pipe system or ducts.

Stop: the shutoff valve that is located under sinks and toilets. Allows for quick water supply shut off at that fixture.

Storage Tank: a tank that is used to hold a specific amount of water measured in volume.

Storm Drain: a drain used to receive and convey rain water, surface water, and ground water running away from buildings.

Sulfate: a chemical water contaminate that has laxative effects and can impart a medicinal taste to water in concentrations around 30 ppm. In high concentrations concurrent with calcium hardness it forms a white insoluble compound that is difficult to remove.

Sulfur: a yellowish solid element. Also, commonly describes water that contains hydrogen sulfide gas, the presence of Sulfur is marked by a smell like rotten eggs.

Sump: A pit or pool for draining, collecting, or storing water. Or a chamber which provides water to a pump for pumping.

Sump Pump: is a pump used to remove water that has accumulated in a sump basin, commonly found in the basements of homes.

Sweating: another term for soldering. Also refers to the formation of condensation on the outside of pipes or toilet tanks.


T-Bolt: The T-Bolt helps in fixing the toilet seats with the floor. It is also called as “closet bolts”.

Tank: It holds water in the flush. Toilets typically holds a tank with a ball cock, jaunt valve and flush lever.

Tank Bolt: It refers to 3 bolts which holds together the tank, basin or bowl of the toilet.

Tank Cover Lock: It is a lock to prevent any damage to the tank, and or helps in covering the tank cover from dust and other bacteria.

Tankless Water Heater:  a water heater design that provides instantaneous hot water.

Tannin (Tannic acid): naturally occurring substance often found in well water produced by decaying vegetation. It may cause water to have a yellow of light brown color and a bitter taste. There is no EPA regulation for tannin levels in water.

Tee: It is any t-shaped fitting used in different plumbing work.

Teflon Tape: sometimes called pipe tape, it’s a plastic fluorocarbon polymer with non-sticking properties used to wrap pipe threads to seal a joint.

Tile-In: It is the installation process, where a sink is fitted with flush and with the countertop.

Total Dissolved Solids: the measurement of the total amount of dissolved minerals in water which contribute to things such as hard water and scaling issues.

Touchless Faucet: faucet or toilet valve that functions automatically using an infrared sensor. Common in commercial applications but sometimes found in homes.

TPI: Stands for “Threads Per Inch”.

Transfer Valve: It is a valve which transfers the flow of water from one pipe to another pipe.

Trip Arm: It is trip lever which is attached with a toilet tank.


ULF: It is an abbreviation for “Ultra Low Flush”.

UNC: It stands for “Unified National Coarse Thread”.

UNF: It stands for “Unified National Fine Thread”.

US EPA: abbreviation for the United States Environmental Protection Agency

US PHS: abbreviation for the United States Public Health Service

Union: It refers to the union, connection of two separate sections of pipes together.

Universal Plumbing Code: system of procedures and regulations that are designed to provide safe and sanitary plumbing conditions and systems through the U.S. with enforcement and regulation via local jurisdictions and municipalities.

Urinal: plumbing fixture which receives only liquid body waste and conveys the waste through a trap seal into a gravity drainage system. Generally, only found in male bathrooms

Urinal Strainers: strainers found in the bottom of urinals to prevent debris from plugging the system.

Usable Storage: represents the volume of hot water that can be drawn off a tank before the temperature drops to a point below standard operating temperate.


Vanity: It is a storage cabinet which is usually found in bathrooms.

Vent: Vents are used to trespass air into different drainage systems to prevent stoppages.

Viscosity: resistance level of fluids against flow due to internal forces and friction between molecules, which increases as its temperature decreases.

Volatile: represents a substance that is capable of vaporization at a low temperature and thus must be handled carefully for safety.

VTR: It stands for “Vent through the Roof”.


Waste Shoe: It usually refers to a drain assembly of a bathtub.

Waste & Overflow Drain: assembly within a bath tub which provides an outlet at the top which removes overflow water during tub filling and the drain at the bottom removes wastewater when the tub is drained.

Waste Plug: drain stopper on a bathtub drain

Water Closet: It is another term used for a toilet.

Water Heater: an appliance consisting of a gas or electric heating unit for heating and usually storing hot water.

Water Table: the level below the Earth’s surface at which the ground reaches a saturation point with ground water.

W.C.: It is an abbreviation for “water closet”.

Weak Well: a weak well condition occurs when the pump draws down the water level in the well faster than the well can replenish itself.

Well Casing: represents a steel or plastic pipe that is inserted into a drilled well to prevent dirt and debris from contaminating the water in the well.

WOG: It is an abbreviation for “Water, Oil and Gas”.

Working Pressure: It refers to normal to maximum compression rate for any plumbing system, valve or pipe.

WYE: It refers to a Y-shaped fitting with three different openings. It is used to connect with different branch lines at the same time.


Yoke: It is usually a metal cap or molding that holds both scorching and frosty valves, along with the blending chamber for the water.

Yoke Vent:  pipe that connects upward from soil or a waste stack to a vent stack for preventing pressure changes in the stacks.


Zeolite: group of hydrated sodium aluminosilicates, either natural or synthetic, with ion exchange properties.

Zero Soft: terming for water with a total hardness less than 1.0 grain per U.S. gallon with calcium carbonate.

Zone of Aeration: layer in the ground above the water table where pocket voids exist filled with air. Water falling on the ground percolates through this zone on its way to the aquifer.

Zone of Saturation: layer in the ground in a condition in which all the available voids are filled with water.

Zone Valve: It is a useful valve which helps in controlling the flow of steam or water in both hydronic heating and cooling structures.