Common Plumbing Terminology Questions

What is a Supply Line?
The portion of the plumbing system connected to the supply of potable water (municipal system, well) that delivers that water to various fixtures in the building.  In most structures, there are two supply lines – one routed through  the hot water heater and the other routed directly from the source for cold water.


What is Dezincification?
Dezincification is the loss of zinc in brass components. This indicates a brass made of poor composition and can be reduced by selecting high quality brass suppliers. More Here


What is a Drain Waste Vent system (DVW)?
The portion of the plumbing system that removes waste water from the  building or home.


What is a fitting?
A general term describing metal or plastic parts designed to connect tubes together or to valves or other fittings.  A wide variety of ends are available.


What is a brass valve?
A general term describing a fitting that can be used to interrupt the flow of water to the rest of the plumbing system.


What is a PEX to Polybutylene tubing?
Polybutylene is made of plastic resin and was popular for installation between 1980-1995. It is often grey while PEX is generally white. These come in elbows, tees and inline adapters. Because of its large installation base, there is a need for PEX to Polybutylene connections. 


What is an elbow?
A fitting with two ends that can change the direction of the water from one tube to another.  The change in direction is most commonly 90° but can be 45° or 60° as well.


What is a tee?
A fitting with three ends where two of the ends are in-line and the third is at 90°.  The sizes for a tee typically start with the two in-line ends and end with the end that is “on top”.  Reducing tees are a useful transition piece when the system needs to transition from one size pipe to another. The measurement of a reducing tee is indicated as left, right and top. So ½ x ½ x ¾ would indicate that the run (or streight part) of the T is ½ and and the 90° top would be ¾.


What is a brass coupling?
A fitting with two, similar ends which are in-line with one another.


What is PEX A, PEX B, PEX C?
These are the three most common types of PEX tubing. Each is selected for use based on the system that is being installed. The primary difference is the flexibility of the piping.


What is PEX aluminum?
Commonly used in creating heated floors, this tubing has an aluminum layer to decrease the oxygen transfer between the contained water system and the atmosphere. This is used only in closed water systems.


What is GHT?
Garden Hose Thread. This brass component is likely the most familiar part because they are used at almost every home. The garden hose thread is unique because it has a female to male thread system. There is also a connection that has a swivel feature so that as you twist the component, you do not twist the attached hose.


What is an adapter?
A fitting with two ends where the two ends are of different mating types.  There are straight adapters and elbow adapters. Male sweat, female sweat, male threaded, female sweat, swivel, AAAA.


What is a drop ear?
A fitting with two or three ends where one end is at a 90° angle to the other (two) and is a female threaded end.  These are commonly used for shower heads but can be used for many purposes.  Technically, they could be called an “adapter elbow” because they connect dissimilar ends which are 90° apart.


What is polybutylene?
Polybutylene is made of plastic resin. It is often grey while PEX is generally white. Because of its large installation base, there is a need for PEX to Polybutylene connections.