About license
Years of training and/or experience are needed to become a skilled plumber; some jurisdictions also require that plumbers be licensed.
Some needed skills, interests, and values
Reading drawings, and specifications to determine layout of water supply, waste, and venting systems
Detecting faults in plumbing appliances and systems, and correctly diagnosing their causes
Installing, repairing and maintaining domestic, commercial, and industrial plumbing fixtures and systems
Locating and marking positions for pipe connections, passage holes, and fixtures in walls and floors
Measuring, cutting, bending, and threading pipes using hand and power tools or machines
Joining pipes and fittings together using soldering techniques, compression fittings, threaded fittings, and push-on fittings.
Testing pipes for leaks using air and water pressure gauges
Awareness of legal regulations and safety issues
Ensuring safety standards and build regulations are met.
United States
Each state and locality may have its own licensing and taxing schemes for plumbers. There is no federal law establishing licenses for plumbers.
United Kingdom
Plumbers in the United Kingdom are required to pass Level 2 and Level 3 vocational requirements of the City and Guilds of London Institute.
Źródło: https://en.wikipedia.org/wiki/Plumber#Plumbing_activities
Connecting a new division of water
Plumbers deal with the installation of water and sewage networks in a new house or new block of flats to be put into use. Then connects the boiler water. It also happens that in the old blocks, there is one department of water and after several years of use of the building administrator decides to perform the second division of water, and by the way checks the patency of the sewage system. Carrying out such work is indeed a nuisance for the residents of the block, but it greatly increases the standard of their daily lives. After their performance will be able to eg. To connect an additional bathroom faucet. Sometimes the desire to connect new devices to the network plumbing associated with the need to perform some plumbing work.
About tools
Plumbing equipment includes devices often hidden behind walls or in utility spaces which are not seen by the general public. It includes water meters, pumps, expansion tanks, backflow preventers, water filters, UV sterilization lights, water softeners, water heaters, heat exchangers, gauges, and control systems.
Specialized plumbing tools include pipe wrenches, flaring pliers, pipe vise, pipe bending machine, pipe cutter, dies and joining tools such as soldering torches and crimp tools. New tools have been developed to help plumbers fix problems more efficiently. For example, plumbers use video cameras for inspections of hidden leaks or problems, they use hydro jets, and high pressure hydraulic pumps connected to steel cables for trench-less sewer line replacement.
Flooding from excessive rain or clogged sewers may require specialized equipment, such as a heavy duty pumper truck designed to vacuum raw sewage.
Źródło: https://en.wikipedia.org/wiki/Plumbing#Equipment_and_tools