Photo: Wakimasa · Public domain · Wikimedia Commons
Lake Toya Hot Spring is a hot spring town in Hokkaido, Japan. The water leaves the ground at 50.3°C, hot. It measures pH 6.7 — close to neutral. Officially the water is classed as chloride spring. Its sources put out around 1,410 litres a minute.
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.
42.5642, 140.8178 — open the map
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