Piped potable water is a pressurised network delivering filtered, clean water from a treatment works to taps, hydrants and homes across a city. Britain built the first comprehensive municipal systems in the 19th century, combining reservoirs, slow sand filtration (pioneered at Chelsea in 1829) and cast-iron mains, increasingly under public ownership after mid-century sanitary reforms. Constant pressure allowed water to reach upper floors and to flush the new sewers.
Clean piped water was a central pillar of the hygienist city, sharply reducing waterborne disease and infant mortality. It made high residential densities healthy and, with sewerage, formed the buried infrastructure on which the modern city depends.