Plumbing

Plumbing, system of pipes and fixtures through which water and drainage flow into and out of a building. Water travels through large underground pipes called mains. These connect with smaller pipes called service lines which bring the water into buildings. A network of pipes distributes the water to fixtures and appliances, providing cold water. One pipe carries water to a hot-water heater, which is connected to pipes that distribute the heated water to fixtures and appliances. The water in pipes is constantly kept under pressure, so that when the faucets or valves are opened, the water will flow out. Drainage pipes carry used water and wastes from sinks, toilets, and appliances, such as washing machines, from a building to a sewer or septic tank. Because they may carry solid materials, drainage pipes are larger than water pipes.