In medieval Bristol, fresh clean water was a valuable commodity and waterborne diseases were rife. For most the only way to get water was to travel to polluted rivers or distant springs and wells.

The town's religious establishments however, appreciated the importance of fresh water and built an underground network of conduits (channels) to carry water from the surrounding hills.

Fortunately for the people of medieval Bristol, the religious orders were generous with their water supply and in 1376, the monks of the Carmelite friary added a small branch pipe to their main conduit, known as St John's Conduit. This branch pipe provided parishioners with fresh water brought down from springs at the top of Park Street. The monks also employed local 'plomere' (lead worker) Hugh White to maintain it. Hugh was paid £10 for the rest of his life in exchange for maintaining and clearing the wooden pipes but lost a whole years payment if the water supply failed for more than 6 days.

St John's Conduit still pipes fresh water from springs at the top of Park Street. Modern pipe markers follow its route to the Church of St John on the Wall in Nelson Street, where it now surfaces.