Plumbing is any system that conveys fluids for a wide range of applications.Heating and cooling, waste removal, and potable water delivery are among the most common uses for plumbing however plumbing's not limited to these applications.1 Plumbing utilizes pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids.2 Trades that work with plumbing such as boilermakers, plumbers, and pipefitters are referred to the plumbing trade.In the Developed world plumbing infrastructure is critical for public health and sanitation. Źródło: https://en.wikipedia.org/wiki/Plumbing#Systems
Water systems of ancient times relied on gravity for the supply of water, using pipes or channels usually made of clay, lead, bamboo, wood, or stone. Hollowed wooden logs wrapped in steel banding were used for plumbing pipes, particularly water mains.
Logs were used for water distribution in England close to 500 years ago.US cities began using hollowed logs in the late 1700s through the 1800s.8 Today, most plumbing supply pipe is made out of steel, copper, and plastic; most waste (also known as "soil")11 out of steel, copper, plastic, and cast iron.11 The straight sections of plumbing systems are called "pipes" or "tubes".A pipe is typically formed via casting or welding, whereas a tube is made through extrusion.
Pipe normally has thicker walls and may be threaded or welded, while tubing is thinner-walled and requires special joining techniques such as brazing, compression fitting, crimping, or for plastics, solvent welding.These joining techniques are discussed in more detail in the piping and plumbing fittings article.Źródło: https://en.wikipedia.org/wiki/Plumbing#Materials
You just have to reckon with the fact that the services contract with an independent plumber probably will prolong the work carried out.
However, this should not affect their quality, and sometimes it turns out that the plumber running his own business applies doubly to perform the outsourced tasks themselves.