Water systems of ancient times relied on gravity for the supply of water, using pipes or channels usually made of clay, lead, bamboo 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 nontoxic material. Present-day drain and vent lines are made of plastic, steel, cast-iron, and 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 and may be threaded or welded, where tubing is thinner-walled and requires special joining techniques such as 'brazing', 'compression fitting', 'crimping', or for plastics, 'solvent welding'.