Natural Thermal Waters
The natural thermal springs in Bath were first discovered by Prince Bladud around 863BC, who was cured from his skin disease after bathing in the waters. The waters were then enjoyed by the Celts, Romans, Saxons and Georgians and are the constant thread throughout the history of Bath.
The water fell as rain around 10,000 years ago and then sank to a depth of about 2km. Here it is heated by high temperature rocks before rising back up through one of the three hot springs in the centre of the City, the Cross Spring, Hetling or King’s Spring, which supplies the Roman Baths.
The actual source of the waters remains a mystery. It was believed that the source was in the Mendip Hills 30 miles to the south of Bath but more recent findings suggest that the rainwater enters through the carboniferous limestone closer to the City and the Avon Valley.
The thermal waters contain over 42 different minerals, the most concentrated being sulphate, calcium & chloride.
Bath has a long association with well-being and the word SPA is associated with the Latin phrase ‘Salus Per Aquam’ or ‘health through water’.
Until the restoration of the Spa was completed in 2006, this natural resource went down the drain and ended up in the river Avon. Today, over 1 million litres of this mineral-rich water flow from the springs each day and are fully used in Thermae Bath Spa.
The thermal water in all four baths at Thermae is the optimum bathing temperature of approximately 33.5°C (92°F).
The water contains over 42 minerals and trace elements. The most concentrated minerals contained within Bath's Hot Springs are as follows:
Mineral Expressed as Concentration (Hetling Spring)
Sulphate Mg/l 1015
Calcium Mg/l 358
Chloride Mg/l 340
Sodium Mg/l 195
Bicarbonate Mg/l 193
Magnesium Mg/l 57
Silica Mg/l 21
Iron Mg/l 0.5