water main

A water main is a pipe or conduit that conveys water as part of a municipal water supply system. These systems are networks of pumps, pipelines, storage tanks, and other components designed to deliver adequate water quantities at sufficient pressures for household use and firefighting, without causing leaks or breaks.123

The pipeline system includes arterial water mains (primary feeders) that transport water from treatment plants to areas of high usage, and smaller secondary feeders that connect to the mains. These pipelines are typically at least 150 mm (6 inches) in diameter and are laid within public rights-of-way to allow for service connections. They are often arranged in a gridiron pattern for circulation, enabling isolation of broken sections for repair without widespread service disruption.2

Water mains must withstand internal and external forces, including water pressure, soil weight, and traffic loads, as well as resist corrosion. They are installed about 1 to 2 meters (3 to 6 feet) below ground to protect against traffic and freezing. Materials used for water mains include asbestos cement, cast iron, ductile iron, plastic, reinforced concrete, and steel.23