Plumbing Terminology - B

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | Y

Backflow Preventers

A Backflow Preventer does just as its name implies, they prevent backflow. Vacuum breakers and other backflow prevention systems are designed to stop gray/dirty water from potentially siphoning back into the water supply and contaminating the fresh water. A typical backflow assembly consists of shut-off valves and test cocks and must be tested each year.


A ballcock is a fill valve that controls the flow of water from the water supply line into a gravity-operated toilet tank. It is controlled by a float mechanism that floats in the tank water.


In the plumbing trade bleeding means to drain a pipe, tube, or hose of excess air by opening a valve at the end or systematically removing the air by force or suction.To remove the air inside your central heating system that has gotten trapped you need to bleed your radiator. Air in a radiator will rise to the top forming a pocket of air and stopping the hot water from getting to it, when there is too much air inside your system it will prevent it from heating properly.

Blow bag

Blow Bag

A blow bag is a device used for drain-cleaning, it is made of a rubber bladder with a hose fitting and a nozzle on the other end. The blow-bag needs to be attached to a water hose and inserted into a clogged drainpipe. When the water is turned on it will fill the blow bag and it expands gripping the pipe. The blowbag releases pulsating bursts of water through the nozzle forcing the water to clear the clog.

Branch vent

The branch vent is connected to the main vent, this pipe serves two or more fixture vents. The branch vent and the fixture vent should be run to a height above the overflow level of the fixture being served. This prevents sewage from draining through the vent line if the fixture waste branch gets clogged.

Building Sewer Service

Building sewer service is a general term that includes both sanitary or storm water drainage piping located within the property line that extends from at least one foot outside the building footings to a legal point of disposal. It does not include the mains of a public sewer system, or a public sewage treatment or disposal plant.

Building Water Service

Building water service is a general term that refers to the pipe from the water main or other source of water supply to the water distribution system of the building served. The water service pipe primarily includes all potable water supply located prior to the connection with the water meter inside the building.