The Plumbing and Pipefitting job series (4200) covers jobs that involve putting in, fixing, and maintaining the pipes that sustain many federal buildings and functions. These jobs are very important for making sure that water, steam, gas, and other fluids can safely and quickly move through complicated networks of pipes and fittings. Depending on the systems they work on, workers in this series may be experts in plumbing or pipefitting.

The pipefitters in this series usually operate with high-pressure systems like steam heating, hydraulic systems, and equipment that makes steam. They have to study and understand blueprints and technical drawings to figure out how to put out and route piping systems. They put in, change, and fix parts like steam generators, pumps, radiators, pressure regulators, and expansion joints. To make sure the system works and is safe, the task needs very exact calculations of pitch, elevation, and pressure.

Plumbers, on the other hand, work on systems that provide water, get rid of sewage, and drain. They put in and fix things like sinks, toilets, and water heaters, and make sure that systems meet safety and sanitation regulations. A lot of the time, they have to fix leaks, blockages, and other problems in homes, businesses, or factories.

There are jobs in this series for those who are just starting out and for people who are already skilled tradesmen. At the trip level (usually Grade 10), workers are required to be able to plan, install, and fix plumbing systems on their own, showing a high level of ability. They need to be good at using tools and equipment, reading technical requirements, and following safety rules.