The thermal water used at "Bibione Thermae" flows at 52 ° C from a source located in the hinterland of Bibione which is over 500 meters deep. Based on the temperature and the dry residue, such water is classified as hyper-thermal medium mineral water and according to the Legislative Decree number 105 dated 25.01.92 it is classified as alkaline bicarbonate, sodium fluoride. Thanks to its features, therapeutic properties have been recognized by the Italian Ministry of Health (Decree n. 2918 and 2950 dated 1996), so for Italian citizens treatment at the Bibione Spa are affiliated with the National Health Service (SSN).
The discovery and the potential of thermal aquifers of the lower Po Valley are due to geological investigations undertaken by AGIP between 1960 and 1970 and aimed at the exploration of hydrocarbons, and later continued by eminent scholars of the CNR and various Italian universities. This research led to the discovery of the last great water resource in Bibione: the hyper-thermal waters that flow from the Mesozoic carbonate basement, the exploitation of which has allowed the realization of the Baths and imprinted an important turning point in the image and in the supply of services by the seaside resort of Bibione.
Geological surveys have detected a geothermal anomaly which has its apex in the hamlet of IV° Bacino of the city of San Michele al Tagliamento (VE), 5 km north of the tourist resort of Bibione, at a depth of about 500 m and a temperature of 52 ° C. The aquifers are normally fed by rainwater infiltration, and their recharge basin invests the vast territory upstream of the distribution area in question, up to the alpine mountains. The outflow of water in the subsoil, with its north-south pattern determines, for the presence of clay layers, the pressurization of the aquifer, which thus assumes the artesian character with pressures from the top of the wells between 1 and 3 atmospheres.
The waters of Bibione Thermae are classified as sodium-bicarbonate-alkaline waters, with the presence of trace elements that demonstrate the contacts with the underlying Mesozoic limestone formation. Since the early eighties geochemical analysis of the thermal waters were commissioned in various institutes, including the National Research Council of Pisa, the University of Padua and Trieste. The classification hydrogeochemistry of the samples was performed using the Piper diagram through which it was possible to detect the uniformity of the water coming from two wells and their classification being "alkaline bicarbonate", to be more precise as "alkaline sodium bicarbonate." In literature it is defined as bicarbonate waters which possess the anion bicarbonate HCO3 predominantly compared to all other anions. Among the alkaline bicarbonate these are distinguished due to the prevalence of sodium with Na Cations.
The waters are now as they were then, bacteriologically pure, and with respect to the amount of dissolved minerals are classified as medium content minerals.
Through a more detailed analysis of the relationships between the various ions present in the waters, complete with correlation isotope diagrams of the geochemistry survey and that of dissolved gases, it was discovered that the samples have characteristics similar to those of the thermal waters of other areas belonging to deep thermal circuits (Sedea 1995), further evidence of the deep hydrothermal circulation that guarantees durability and potential of the hydrothermal resources.
Currently, the chemical analyses are carried out by ARPAV (Regional Agency for Environmental Prevention and Protection of Veneto), accredited for the analysis of thermal water samples of the Veneto Region.