南部アルカディア温泉 is a hot spring town in Yamanashi, Japan. The water leaves the ground at 49.5°C, hot. It measures pH 9.9 — strongly alkaline. Officially the water is classed as simple spring. Its sources put out around 412 litres a minute.
Mild and low in dissolved minerals. Usually clear and gentle on the skin, which is why these baths are often recommended for first-timers.
Figures from the town's Japanese Wikipedia article.
35.2800, 138.4633 — open the map
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