Plumbing Glossary

Let’s take a look at what some common plumbing terms mean.


Standing for acrylonitrile butadiene styrene, this is a kind of plastic pipe that is used in vents, drains, waste lines and more.

Absorption Field

One of the areas used for the treatment of sewage right after passing through a septic tank.

Access Panel

A space in the wall or ceiling that can connect a fitting or fixture to the plumbing network.


A component fitted to a faucet to regulate water flow by mixing air with it.

Back Flow

Reverse flow or reflux of water or liquid into a component of the main plumbing system instead of its correct or normal direction.


A structure used to regulate the flow of water in a toilet cistern. It falls and rises with the water level in the tank.


A container or vessel to hold water while washing hands. It is also called a sink by large populations.


A fixture near a toilet that sprays out water for washing up after using the toilet.

Black Water

The dirty or wastewater that collects in the toilets and passes through drainage.

Check Valve

A structure to keep water flowing in a single direction without any reflux.

Circuit Vent

A vent to support 2-8 fixtures on a horizontal drain line. It is connected from the two extreme vents to the main vent.


A stopper installed in a pipe or vent to clean up any blockages.

Cycle Time

The time period of a flushing system in a toilet, starting from the time that you flush the toilet to the time it takes to refill the tank.


A valve that allows the water to flow to different fixtures like showers, faucets and bidets.


An internal vessel that gets rid of the wastewater from sinks, toilets or bathrooms.

Dynamic Pressure

The water pressure that exists while flowing from one part to another in the entire plumbing system.


The liquid waste from septic tanks that is usually discharged into water bodies after sufficient treatment.

Expansion Tank

A tank that is able to withstand extra pressure that is exerted when expansion takes place due to heat.


A structure that joins two pipes or sections with each other.


The toilets, sinks, tubs or any other general structure fitted in a bathroom or kitchen; also tends to refer to faucets that provide water to the structures.

Flow Rate

The rate at which water flows through a pipe or drain.


Gallons per minute or gallons per hour. A measuring unit to explain the flow rate.

Grey Water

The dirty or wastewater from showers, sinks and other fixtures (does not include toilet water).

Hard Water

Water that contains lots of minerals or impurities such as calcium and magnesium.

Heat Exchanger

An appliance used to exchange or transfer heat between two mediums; used for both heating and cooling.

Heat Trap

A seal or trap that is meant to hold in the heat inside a structure instead of letting it escape.


Inside diameter that reflects the size of a pipe.


All parts of a faucet that help control the flow of water into a sink or tub. These could either be the handles or the levers and rings.


A basin or vessel that contains a faucet with running water. It could also be used to describe toilets or bathrooms in general.

Leach Lines

Pipes placed on soil, used for transporting the effluent into the disposal site or field from septic tanks.

Maximum Contaminant Level

The maximum limit of a contaminant or substance that is allowed in drinking water. This limit is usually set by the Environmental Protection Agency (EPA).

Male Threads

A fitting that is inserted into another fitting that has a larger opening.


The approximate size or inside diameters of a pipe that is used for identification.


The outside diameter of a pipe reflecting the size of the pipe from its external end. It is usually slightly larger than the internal diameter.

Perforated Pipe

A pipe that has several small holes all over it from which water can sprinkle out onto the desired area. This can be used in plumbing to get rid of extra water at a given time.


A ceramic material made using heat. It is often used to make bathroom and kitchen sink fixtures. It is usually white and glossy in appearance.


Generally used to describe drinking water that is safe for consumption.

Refill Tube

A tube that carries water into the toilet bowl from the overflow tube in order to refill the bowl after flushing.

Relief Vent

A vent that forms an important part of the drain line or system. It is mainly used to maintain the air pressure so that it does not fluctuate too much in comparison with the external atmospheric pressure.


A tube that carries water from a container and then drops it off into another lower container.

Soft Water

Water that is usually separated from minerals deposits that are dissolved in hard water but that still contains salts.


In plumbing, a tank usually refers to a toilet tank or system that stores water for flushing. It is refilled each time you flush the toilet and contains a chain, valves and a ballcock.


Also referred to as a faucet, a tap is a cylindrical structure that ejects water into a fixture.

Trap Seal

A seal used to maintain the level of water inside a toilet bowl, forming a trap to prevent toxic sewage gases from entering the bathroom and house.


A structure that can open and shut, allowing or controlling the flow of water from one medium to another.


A structure or pipe used to keep the air pressure in check and avoiding sewer gases from entering common areas of the house.

Water Hammer

The sound that occurs whenever you switch off the water supply into a particular fixture.

Working Pressure

The regular pressure at which any plumbing structure or fixture operates.

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