Federal job category 4200 includes skilled trades focused on the installation, maintenance, and repair of plumbing and pipefitting systems across federal facilities. These roles involve working with water supply lines, drainage systems, steam heating, hydraulic piping, and fuel distribution networks. Employees in this category may be plumbers, pipefitters, or fuel system mechanics, responsible for reading blueprints, laying out pipe routes, assembling fittings, and ensuring systems operate safely and efficiently. The work requires knowledge of fluid dynamics, pressure ratings, and safety codes, along with hands-on experience using tools like pipe cutters, threaders, and welding equipment.

Most positions fall under the Federal Wage System and are physically demanding, often performed in tight spaces, underground areas, or elevated platforms. Workers may be stationed at military bases, correctional facilities, or government buildings, supporting everything from daily operations to emergency repairs. Whether installing high-pressure steam lines or troubleshooting leaks in potable water systems, GS-4200 roles demand precision, problem-solving skills, and a strong commitment to safety and reliability. These jobs are essential to maintaining the infrastructure that keeps federal operations running smoothly.