Plumbers install and maintain water supply, drain-waste-vent (DWV), and gas piping systems. Licensed plumbers complete 4-5 year apprenticeships and pass journeyman exams. Work includes designing water distribution, installing fixtures, troubleshooting leaks, and maintaining code compliance. Plumbers work with various materials including copper, PVC, PEX, cast iron, and galvanized steel. Typical hourly rates range from $40-$80, with union rates higher. In union markets, plumbers typically belong to the United Association of Plumbers and Pipefitters (UA) union. Specializations include medical gas, backflow prevention, fire suppression, and green plumbing technologies. Plumbers must follow the International Plumbing Code (IPC) and local amendments.