Plumbing Terms

ABS Acrylonitrile-Butadiene-Styrene; a rigid plastic drainpipe
Adapter Connects one type of pipe to another
Cap Fitting with a solid end used for closing off a pipe
Center-to-center In mounting faucets: the distance between centers of holes on a sink deck.
In pipefitting:Distance between centers of two consectutive pipes.
Cleanout Opening providing access to a drainline or trap; closed with a threaded cleanout plug.
Compression Fitting Easy-to-use fitting for copper or plastic tube. Pushed in and hand-tightened
Compression Nut Used with a compression ring to join a flexible tube to a compression fitting.
Coupling Fitting used to connect two lengths of pipe in a straight run.
Coupling Nut Holds a supply tube to a faucet inlet or a toilet inlet valve.
CPVC Chlorinated polyvinyl chloride; rigid plastic tube for hot and cold water.
Critical distance Maximum horizontal distance allowed between a fixture trap and a vent or soil stack.
Cross connection Plumbing connection that could mix contaminated water with potable water supply.
DWV Drain-waste and vent; system that carries away waste water and solid waste, allows sewer gases to escape, and maintains atmospheric pressure in drain pipes.
Elbow Fitting used for making turns in pipe runs (i.e. and 90° elbox makes a right-angle turn)
Escutcheon Decorative trim piece that fits over a faucet body of pipe extending from a wall.
Female Pipes, valves, or fittings with internal threads.
Fitting A device used to join pipes.
Fixture A non-powered water-using devide such a sink, bathtub, shower, or toilet.
Flange Flat fitting or integral edging with holes to permit bolting together (a toilet bowl is bolted to a floor flange) or fastening to another surface (a tub is fastened to a wall through an integral flange).
Flare Fitting Threaded fitting used on copper and plastic pipe that requires enlarging one end of the pipe
Flexible Connector Bendable piece of tubing that delivers water from a shutoff valve to a fixture or appliance.
Flue Large pipe through which fumes escape from a gas water heater.
Gasket Device (usually rubber) used to make a joint between two parts watertight. Sometimes used interchangeably with washer.
Hose Bibb Valve with an external threaded outlet for accepting a hose fitting.
Joist A horizontal wood framing member placed on edge, as a floor or ceiling joist.
Locknut Nut used to secure a part, such as a toilet water inlet valve, in place
Male Pipes, valves, or fittings with external threads.
Nipple Short piece of pipe with male threads used to join two fittings.
No-hub Cast-iron pipe joined with neoprene gaskets and clamps
O-ring Narrow rubber ring; used in some faucets as packing to prevent leaking around stem and in swivel-spout faucets to prevent leaking at base of spout.
Packing Material that stops leaking around the stem of a faucet or valve.
PB Polybutylene; flexible plastic tubing for hot or cold water.
PE Polyethylene; flexible plastic tubing for cold water outdoors.
Pipe Drain pipe or supply pipe that is sized nominally by iron pipe sizes.
Pipe-joint compound Sealing compond used on threaded fittings (applied to external threads).
Pipe-thread tape Special tape used as a joint sealer in place of pipe-joint compound.
Plug Externally-threaded fitting for closing off a fitting that has internal threads.
PP Polypropylene; rigid plastic pipe used for traps
Pressure regulator Device installed in a water supply line to reduce water pressure.
PVC Polyvinyl Chloride; rigid plastic pipe for cold water outdoors or off-white piping used for DWV systems.
Reducer Fitting that connects pipe of one diameter with pipe of a smaller diameter
Riser Vertical run of pipes.
Saddle tee T-fitting that is fastened onto side of pipe, eliminating cutting and threading or soldering; usually requires drilling into pipe.
Sanitary fitting Fitting with smooth bends and no inside shoulders to block flow of waste; used to join DWV pipe.
Silicone grease A type of synthetic grease used to lubricate faucet parts; non-petroleum base, won’t break down rubber parts.
Siphoning Action occuring when atmospheric pressure forces water into a vacuum in a pipe.
Slip Coupling Used to join a new fitting into a run of copper or plastic tubing. It is unthreaded and has no center shoulder,so it can slide along a tube.
Slip Nut Used on a drain (such as a sink trap). Threads onto one pipe and compresses a washer around the other to form a slip joint.
Soil stack Large DWV pipe that connects toilet and other drains to house drain and also extends up and out house roof (the upper portion serving as a vent).
Solvent Cement Compound used to join rigid plastic pipes and fittings.
Spacer Short piece of unthreaded plastic or copper pipe cut to size; used when reparing or extending pipe. Sometimes referred to as a nipple.
Stubout End of a supply pipe or drainpipe that extends from a wall or floor
Stud A vertical wood framing member; also known as a wall stud. Attached to a sole plate below and a top plate above.
Sweat soldering A method of using heat to join copper tube and fittings.
T-fitting Also known as a tee, it is a T-shaped fitting with 3 openings.
Transition fitting Adapter fitting that joins pipes of plastic and metal.
Trap Device (usually a curved section of pipe) that holds a water seal to prevent sewer gases from escaping into a home through a fixture drain.
Tube Supply pipe that is sized nominally by copper water tube sizes.
Union Fitting that joins two lengths of pipe permitting assembly and disassembly without taking the entire section apart.
Valve Device that controls that flow of water.
Washer A flat thing ring of metal or rubber used to ensure a tight fit and prevent friction in joints and assemblies. Sometimes used interchangeably with gasket.
Y-Fitting Or wye; DWV fitting with 2 outlets in shape of the letter Y.