The spring temperature is 9 - 13o C, total mineralisation is 6700 mg/l. CO2 content is more than 1200 mg/l. It is ferrous acidulous water of bicarbonate-sulphate-soda type with increased content of fluorides, hypotonic, moderately mineralised. For its high content of carbon dioxide it can be important from the balneologic point of view and for possible indications for drinking cure. Content of the most of trace and secondary elements corresponds to that of classical Carlsbad hot springs, content of selenium, iron and zinc, however, is increased and the source also shows increased content of natural hydrogen sulphide. In 1884, basin of the _těpánka Spring was dug in proximity of the present-day Bath IV, i.e. on the southern edge of extrusion zone of Carlsbad hot-spring structure. However, in the first decades of 20th century, the source disappears. A new well was established only after several unsuccessful attempts in 1993.
