宇津江四十八滝温泉 is a hot spring town in Gifu, Japan. The water leaves the ground at 30°C, cool enough that the baths here are usually reheated. It measures pH 8.3 — mildly alkaline, the slippery kind. Officially the water is classed as simple spring. Its sources put out around 248 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.
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