Plumbers install, repair and maintain plumbing fixtures and systems, including water, steam, chemical, medical gas, process piping, irrigation and fuel piping systems. They are employed by plumbing contractors, maintenance departments of manufacturing, commercial, health care and educational facilities, and by plumbing service companies. They may also be self-employed. Plumbers install piping and equipment in residential, commercial, institutional and industrial buildings. They may also install specialized equipment such as medical gas equipment, compressed air equipment, residential fire systems, water conditioners, sewage and water treatment, and storage and flow systems for toxic waste.

Plumbers interpret blueprints, refer to layouts of existing services, and review applicable codes and specifications to determine work details and procedures. They locate and mark positions for fixtures, pipe connections and sleeves, then cut openings to accommodate pipe and fittings. Plumbers use a variety of tools and equipment, including power tools, welding and soldering/brazing equipment, and hoisting and lifting equipment to perform the tasks in their trade. They work with a variety of piping materials including copper, steel, plastic, glass, cast iron, asbestos-cement pipe and specialty pipe. Before assembling and fitting pipe sections, tubing and fittings, the pipes must be measured, cut and bent as required. Joining pipe may be done by various means, including threading, mechanical joints, welding, soldering/brazing and using fastening materials and compounds. Once the system is in place, plumbers test pipes and plumbing fixtures to detect and locate leaks.

There is an inherent risk of injury when working with sharp edges, power tools, pipe-joining equipment and chemicals. Special considerations must be taken to avoid serious injury when working with pressurized fluids, gases and steam. Other hazards include exposure to the elements, electrical shocks, burns, heavy lifting and exposure to hazardous waste. While performing their duties, plumbers are also required to do considerable standing, climbing, and kneeling. They must often work at heights and in cramped, awkward positions. Key attributes for people entering this trade are good mechanical, mathematical and spatial visualization skills. Plumbers also need good communication skills to communicate with clients and co-workers. Good analytical skills are required to interpret building plans and inspect plumbing systems.

With experience, plumbers may act as mentors and trainers to apprentices in the trade. They may move into other positions such as instructors, estimators and project managers. This analysis recognizes similarities or overlaps with the work of gas fitters, steamfitters/pipefitters and sprinkler system installers.