The water is sourced from rainfall on the nearby Mendip Hills, which then percolates down through limestone aquifers to a depth of between 2,700 and 4,300 metres (8,900 and 14,100 ft).

This duty has now passed to Bath and North East Somerset Council, who monitor pressure, temperature and flow rates.

Archaeological evidence indicates that the site of the baths may have been a centre of worship used by Celts;[10] the springs were dedicated to the goddess Sulis, who was locally identified with Minerva.

Geoffrey of Monmouth in his largely fictional Historia Regum Britanniae describes how the spring was discovered by the pre-Roman British king Bladud, who built the baths there.

[11] Early in the 18th century Geoffrey's obscure legend was given great prominence as a royal endorsement of the waters' qualities, with the embellishment that the spring had cured Bladud and his herd of pigs of leprosy through wallowing in the warm mud.

[13] During the Roman occupation of Britain, and possibly on the instructions of Emperor Claudius,[14] engineers drove oak piles into the mud to provide a stable foundation and surrounded the spring with an irregular stone chamber lined with lead.

[15] After the Roman withdrawal from Britain in the first decade of the 5th century, these fell into disrepair and were eventually lost due to silting up,[16] and flooding.

[28] The museum and Queen's Bath including the "Bridge" spanning York Street to the City Laundry were by Charles Edward Davis in 1889.

[29] The museum houses artefacts from the Roman period, including objects that were thrown into the Sacred Spring, presumably as offerings to the goddess.

[31] The Bath Roman Temple stood on a podium more than two metres above the surrounding courtyard, approached by a flight of steps.

It featured the powerful central image of a possible "Gorgon" head glowering down from a height of 15 metres (49 ft) on all who approached the temple.

[15] Besides the Gorgon head, the pediment's artistic motif has more recently also been compared to the Jupiter-Ammon clipei found throughout Roman fora and which sometimes depicted local river gods in Celtic provinces.

[40] Exhibits within the temple precincts are susceptible to warm air which had the effect of drawing corrosive salts out of the Roman stonework.

[43] Subsequent grants have funded further work on the exhibition design and layout by London-based specialist firm, Event Communications.