Plumbing Terms - Glossary of Plumbers Terminology

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Quick Coupler

A quick coupler or quick-action coupler is used in a hydraulic or pneumatic system to quickly connect lines without losing fluid or fluid pressure.  All couplings consist of two mating halves: the plug (male) and the coupler (female). Couplers can be used under a variety of pressure and temperature conditions. 


A reducer is the component in a pipeline that reduces the pipe size from a larger to a smaller bore (inner diameter). The length of the reduction is usually equal to the average of the larger and smaller pipe diameters. A reducer can be used either as nozzle or as a diffuser, depending on the mach number of the pipe that is used to direct the flow.

Rim Holes

Rim holes are a series of small holes in the underside of a toilet rim, around the circumference of the bowl. Incoming water flows down into the bowl through these holes, creating a rinse effect or wash over the entire inner surface of the bowl.

Rim Holes

With rim holes are meant the series of small holes underneath the toilet rim, around the circumference of the bowl. The incoming water flows down into the toiletbowl through these holes and creates the rinsing effect to make it wash over the entire inner surface of the toilet bowl.


Risers are vertical metal or plastic tubes or assemblies that connects a faucet to the water supply stop valve. Usually made of copper. Metal Flex Risers are corrugated to facilitate bending. Also a supply line that rises from one story to the next.

Rough Plumbing

Rough Plumbing is a term used in the plumbing and contruction industry to point to a stage in construction when the plumbing is actually roughed in before the walls are covered up with sheet rock or other wall finishes.


An S-trap is a plumbing trap that takes the shape of the letter S and is used where a waste pipe feeds into the floor instead of the wall, which uses a P Trap. Disallowed in many parts of the country, they can create a siphoning situation, pulling water out of the trap.

Sanitary Separator

A sanitary separator is a device designed and installed to separate hazardous or undesirable matter from normal wastes while permitting normal sewage or liquid wastes to discharge into the drainage system by gravity flow. This is the same definition as an interceptor with the only difference being the intended function of the device.

Self-amalgamating Tape

self-amalgamating tape A very useful derivative of insulating tape which can be used for waterproofing connections. To use, the top protective layer is peeled off and the rubbery self amalgamating tape underneath is wrapped tightly around the connection to be waterproofed. This type of tape self-fuses or amalgamates without any added adhesive.

Shutoff Valve

With a shutoff valve usualy is meant the angle stop beneath each fixture, but may also refer to the main valve by the water meter or valves on the branch lines. In case of an emergency, the water flow should be terminated using the shutoff valves.

Stack Test

A Stack Test is a term used in the plumbing trade to refer to filling a stand pipe normally 10 foot in height with water and let sit for a period of time. This is to test normally the sanitary drain in a house or inner foundation.


A stopcock is a valve that regulates the flow of fluid through a pipe; a faucet. There are usually two stopcocks for a home. One is usually found just outside the property boundary and can be used to isolate the building from the water supply. The other is inside the property where the supply enters the property. These valves are provided to allow maintenance and prevent flooding if the domestic water system is pierced.

T&P Valve

A T&P Valve or Temperature & Pressure Relief Valve is a safety device used to expel excess pressure or heat from inside a tank.

Tee Fitting

A Tee Fitting also know as a Tee or T-fitting is used to either combine or split the waterflow. Most common are tees with the same inlet and outlet sizes, but 'reducing' tees are available as well. Tee fittings have three-ports and are in the shape of a "T".  Standard configuration ("Equal") indicates that the straight-through path (typically called the "run") and the perpendicular section ("branch") all have the same size ports.

Thermostatic Valve

A thermostatic valve is a pressure-balancing shower mixing valve with automatic temperature control. When the water temperature or water pressure fluctuates at the water inlets, a thermal actuator inside the thermostatic valve adjusts the hot and cold ratio maintaining the original temperature setting.