The spas in the area are known nationally thanks to the peculiarity of their waters that flow naturally at temperatures between 35 and 55 Celsius degrees; besides large holiday complexes that offer spa sessions for a fee, there are free zones (or ponds) where you can enjoy free water in an untouched nature.

The town of San Casciano dei Bagni is surrounded by woods of oak and chestnut trees; in this frame  there are 42 sulphate, calcium and fluoride springs; the waters flow at a temperature of about 37 Celsius degrees.
Also there are many ponds, natural pools surrounded by greenery, where you can enjoy total relaxation in the quiet of the woods, in close contact with nature.

Located in the Park of Val d’Orcia are the Thermae of San Filippo, the uniqueness of these ponds are the beautiful limestone deposits formed by hot sulphurous thermal waters, which since the Middle Ages took care of famous people, including Lorenzo the Magnificent and Grand Duke Ferdinando II. They became famous thanks to the Machiavellian quote La Mandragola.
Along the way of Fosso Bianco (White Ditch, the river Rondinaia nickname gaven because of the color its waters take on mixing with thermal water) you can find free ponds areas, with small solidified waterfalls, capable of giving unique moments of pleasure and relaxation; the most known is the Balena Bianca, White Whale.

The Terme di Saturnia hot sulphorous waters are perhaps the oldest; were already known to the Etruscans who had identified in that source some kind of miraculous. Next was the Romans who benefit by building homes for therapeutic exploitation of the source; nowadays can still be seen numerous exhibits to witness the work of the Romans.
In the Middle Ages, due to water vapor, heat given off and the smell of sulfur, many legends took life: it was said that the devil came out of the water when it left the underworld. The territory was described as a place where water flowed bewitched, who came to settle in pools and steaming hot, filling the air with a sharp satanic smell.
In the Middle Ages were mentioned by Pope Clement III, who had appreciated the carbonated mineral sulfur-sulfate-bicarbonate-alkaline in the waters, aswell including, among its features, the presence of two dissolved gases such as hydrogen sulfide and carbon dioxide.
Free ponds can be found steps away from the center of Saturnia, in Molino (which takes its name from the presence of an old mill just to the side of the falls), are enjoyable in all times.