Plumbing Basics

Plumbing (from the Latin plumbum for lead, as pipes were once made from lead) is the skilled trade of working with pipes, tubing & plumbing fixtures for drinking water systems & the drainage of waste. A plumber is someone who installs or repairs piping systems, plumbing fixtures & equipment such as water heaters. The plumbing industry is a basic & substantial part of every developed economy due to the need for clean water and proper collection & transport of wastes.

Plumbing also refers to a system of pipes & fixtures installed in a building for the distribution of potable water & the removal of waterborne wastes. Plumbing is usually distinguished from water & sewage systems, in that a plumbing system serves one building while water & sewage systems serve a group of buildings or a city.

Plumbing was extremely rare until the growth of modern cities in the 19th century. At about the same time public health authorities began pressing for better waste disposal systems to be installed. Earlier, the waste disposal system merely consisted of collecting waste & dumping it on the ground or into a river. Standardized earthen plumbing pipes with broad flanges making use of asphalt for preventing leakages appeared in the urban settlements of the Indus Valley Civilization by 2700 B.C. Plumbing originated during the ancient civilizations such as the Greek, Roman, Persian, Indian & Chinese civilizations as they developed public baths & needed to provide potable water & drainage of wastes. The Romans used lead pipe inscriptions to prevent water theft. Improvement in plumbing systems was very slow, with virtually no progress made from the time of the Roman system of aqueducts & lead pipes until the 19th century. Eventually the development of separate, underground water & sewage systems eliminated open sewage ditches & cesspools. Most large cities today pipe solid waste to treatment plants in order to separate & partly purify the water before emptying into streams or other bodies of water. For potable water use, galvanized iron piping was commonplace in the United States from the late 19th century until around 1960. After that period copper took over, first with soft copper with flared fittings & then with rigid copper tubing utilizing soldered fittings. The use of lead for potable water declined sharply after World War II because of the dangers of lead poisoning. At this time, copper piping was introduced as a better & safer alternative to lead pipes.

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. Present-day water supply systems use a network of high-pressure pumps and pipes are now made of copper, brass, plastic or other non-toxic material. Present-day drain and vent lines are made of plastic, steel, cast-iron & lead. Lead is not used in modern water supply piping due to its toxicity.

The "straight" sections of plumbing systems are of pipe or tube. A pipe is typically formed via casting or welding, where a tube is made through extrusion. Pipe normally has thicker walls & may be threaded or welded, where tubing is thinner-walled & requires special joining techniques such as brazing, compression fitting, crimping or for plastics, solvent welding.