Plumbers install or repair water supply lines, drainage systems, and gas systems in a variety of construction work environments. Plumbers measure, cut, and install plastic, copper, steel, and cast iron pipe. In the rough-in phase, plumbers may attach or hang pipes for connection to fixtures. In the trim-out phase, they may install sinks, toilets, and appliances. The Associated Builders and Contractors San Diego (ABCSD) Apprenticeship program is a state and federally recognized construction training program. Apprenticeship Career and Technical Education (CTE) combines paid on-the-job training and work experience with formal classroom instruction. Apprentices are employed by a company where they receive hands-on training and attend classes in the evening to study theory and participate in hands-on technical training.