Welcome to the Building Industry Association of Southern California, Orange County Chapter (BIA/OC). The Building Industry Association of Southern California (BIA/SC) is a non-profit trade association representing 1100 companies affiliated within the homebuilding industry throughout Southern California. The Orange County Chapter is one of four chapters that make up BIA/SC, and is also affiliated with the California Building Industry Association (CBIA). An active board of directors and 9 volunteer committees, made up of leaders from local builders, trade contractors and businesses associated within the real estate industry, lead BIA/OC in its mission.