Plumbing refers to pipes and fixtures installed in a building or structure to move liquid. The two most common uses of plumbing includes the distribution of potable water (water that is safe to drink) and the removal of waste. The word "plumbing" is derived from the Latin word for lead, "plumbum."

Plumbing systems have been in use since the ancient times and are an essential element of a civilized society. Early plumbing systems relied on gravity to move water through pipes or channels made of the materials common for the day. In modern times, pumps, water heaters, and other devices have been invented for better control and ease of moving and using water. Stronger, more workable, and safer materials are now used to construct piping materials -- including steel, plastic, copper, etc.

Local governments typically inspect and authorize plumbing systems for public use, due to public health considerations. Potable water must remain safe and uncontaminated from its source and to the end user. Likewise, waste water must be directed to the appropriate sewage or septic system and processed correctly to avoid harming people, animals, and the environment.

The four most common elements of a plumbing system include: