The Great Conduit was a man-made underground channel in London, England, which brought drinking water from the Tyburn to Cheapside in the City.
In 1237 the City of London acquired the springs near the Tyburn and built a reservoir to provide a head of water for serving the city. Work on building the conduit began in 1245. It ran towards Charing Cross, along the Strand and Fleet Street and round the southern side of the city. It then ran along Cheapside where there was a building where citizens could draw water. Wardens were appointed to prevent unlawful access and use and to repair pipes. Extensions were made to the system leading to various parts of the city. Other conduits were constructed in the 15th Century.
Use of the conduit ceased after the Great Fire of London in 1666.