204.0 – B –

Backflow. The flow of water or other liquids, mixtures, or substances into the distributing pipes of a potable supply of water from sources other than its intended source. See Backpressure Backflow and Backsiphonage. Backflow Connection. An arrangement whereby backflow

can occur.

Backflow Preventer. A backflow prevention device, an assembly, or another method to prevent backflow into the potable water system. Backpressure Backflow. Backflow due to an increased pressure above the supply pressure, which may be due to pumps, boilers, gravity, or other sources of pressure. Backsiphonage. The flowing back of used, contaminated, or polluted water from a plumbing fixture or vessel into a water supply pipe due to a pressure less than atmospheric in such pipe. See Backflow. Backwater Valve. A device installed in a drainage system to prevent reverse flow.

Bathroom. A room equipped with a shower, bathtub, or combination bath/shower.

Bathroom, Half. A room equipped with only a water closet and lavatory. Bathroom Group. Any combination of fixtures, not to exceed one water closet, two lavatories, either one bathtub or one combination bath/shower, and one shower, and may include a bidet and an emergency floor drain. Battery of Fixtures. A group of two or more similar, adjacent fixtures that discharge into a common horizontal waste or soil branch.

Bedpan Steamer. A fixture that is used to sterilize bedpans by way of steam.

Body Spray. A shower device for spraying water onto a bather from other than the overhead position.

Boiler Blowoff. An outlet on a boiler to permit emptying or discharge of sediment.

Bonding Jumper. A reliable conductor to ensure the required electrical conductivity between metal parts required to be electrically connected. [NFPA 70:100 (Part I)] Bottle Filling Station. A plumbing fixture connected to the potable water distribution system and sanitary drainage system that is designed and intended for filling personal use drinking water bottles or containers not less than 10 inches (254 mm) in height. Such fixtures can be separate from or integral to a drinking fountain and can incorporate a water filter and a cooling system for chilling the drinking water.

Branch. A part of the piping system other than a main, riser, or stack.

Branch, Fixture. See Fixture Branch.

Branch, Horizontal. See Horizontal Branch.

Branch Vent. A vent connecting one or more individual vents with a vent stack or stack vent.

Building. A structure built, erected, and framed of component structural parts designed for the housing, shelter, enclosure, or support of persons, animals, or property of any kind. Exceptions: [HCD 1 & HCD 2] “BUILDING” shall not include the following:

1. Any mobilehome as defined in Health and Safety Code Section 18008.

2. Any manufactured home as defined in Health and Safety Code Section 18007.

3. Any commercial modular as defined in Health and Safety Code Section 18001.8 or any special purpose commer- cial modular as defined in Section 18012.5.

4. Any recreational vehicle as defined in Health and Safety Code Section 18010.

5. Any multifamily manufactured home as defined in Health and Safety Code Section 18008.7.

For additional information, see Health and Safety Code Section 18908.

Building Drain. That part of the lowest piping of a drainage system that receives the discharge from soil, waste, and other drainage pipes inside the walls of the building and conveys it to the building sewer beginning 2 feet (610 mm) outside the building wall. Building Drain (Sanitary). A building drain that conveys sewage only. Building Drain (Storm). A building drain that conveys storm water or another drainage, but no sewage. Building Sewer. That part of the horizontal piping of a drainage system that extends from the end of the building drain and that receives the discharge of the building drain and conveys it to a public sewer, private sewer, private sewage disposal system, or another point of disposal. Building Sewer (Combined). A building sewer that conveys both sewage and storm water or other drainage.

32 2025 CALIFORNIA PLUMBING CODE

DEFINITIONS

Building Sewer (Sanitary). A building sewer that conveys sewage only. Building Sewer (Storm). A building sewer that conveys storm water or another drainage, but no sewage. Building Subdrain. That portion of a drainage system that does not drain by gravity into the building sewer. Building Supply. The pipe is carrying potable water from the water meter or another source of water supply to a building or other point of use or distribution on the lot.