The spa area of São Pedro do Sul is part of an extensive massif of granites. The origin of the thermal water appears, according to the expert geologists, of a great active tectonic fault that extends itself in this region. It can conduct groundwater flows of great distances and depths.

The thermal water emerges from the interior of the earth to the surface with a natural temperature of 68,7º C. It is characterized as weakly mineralized, “sweet”, with a very alkaline reaction. It is bicarbonated, sodium, carbonated, fluoridated, sulfidated and strongly silicated.

This water belongs to a group called sulphurous waters, being the sulfur the responsible element for its characteristic smell. It has maintained its physical-chemical stability for thousands of years and it is bacteriologically pure.

Due to its unique composition, it has recognized therapeutic effects when used in thermal curing programs.

Typical physicochemical characterization:

Temperature: 68,7 ºC
pH= 8,82 (a 20ºC), 
Total Mineralization=356,6mg/L 
Total Sulfuration= 21,2mL/L,
Bicarbonate (HCO3-)= 117,2mg/L, 
Sodium(Na+)= 89,9mg/L, 
Fluoride (F-)= 17,5mg/L,
Total Silica (SiO2)= 73,8mg/L.