Water systems of ancient times relied on gravity for the supply of water, using pipes or channels usually made of clay, lead or stone. Plumbing originated during the ancient civilizations of the Chinese, Greeks and Romans. Present-day water-supply systems use a network of high-pressure pumps, and pipes and are now made of copper or brass, plastic, or other non-toxic material. Plumbing and drain lines are now made of plastic, steel, cast-iron, and non-toxic lead products.
Plumbing equipment and supplies may include, for example, water meters, pumps, expansion tanks, backflow preventers, filters, water softeners, water heaters, gauges, and control systems. Plumbing fixtures are generally defined as water fountains, bathroom toilets, showers, bathtubs, kitchen and bathroom sinks and other household water utilities.