塩ノ沢温泉 is a hot spring town in Fukushima, Japan. The water leaves the ground at 21.5°C, cool enough that the baths here are usually reheated. Officially the water is classed as radioactive spring. 1 inns take visitors here.
Contains trace radon that leaves the water quickly. Also called radium or radon springs.
Figures from the town's Japanese Wikipedia article.
Planning a first soak? Read how an onsen stay works, and what to do if you have tattoos.