
Photo: 皓月旗 · CC BY-SA 4.0 · Wikimedia Commons
Echigo Nagano Onsen is a hot spring town in Niigata, Japan. The water leaves the ground at 15.5°C, cool enough that the baths here are usually reheated. It measures pH 7.4 — close to neutral. Officially the water is classed as chloride spring. Its sources put out around 21 litres a minute. 1 inns take visitors here.
Salty water. The salt leaves a thin film on the skin, so you stay warm well after leaving the bath.
Figures from the town's Japanese Wikipedia article.
37.5269, 139.1181 — open the map
Planning a first soak? Read how an onsen stay works, and what to do if you have tattoos.