Nomizo Onsen Senju no Yu

Located in Sasa, Kimitsu City, Chiba Prefecture, Nomizo Onsen Senju no Yu is a day-use hot spring facility at the entrance to Shimizu Gorge Park along the upper Sasa River. Its water rises naturally from the bed of the Sasa River, and it is the only bathing facility drawing on this source. It sits quietly behind the nearby Nomizo Falls and Kameiwa Cave, a spot known for the heart-shaped light reflection created when sunlight passes through the rock tunnel onto the water.

The spring is classified as a sodium bicarbonate spring with a mildly alkaline pH of 8.63. Because the source temperature is only 15.5°C, the water is gently heated before use, yet it is never diluted, filtered through a circulation system, or chemically disinfected — a genuine source-fed bath that is rare in Chiba Prefecture. Known as a 'beauty-skin bath,' the faintly yellow-tinged, clear water leaves skin feeling soft and smooth, with a subtle mineral scent.

The bathing area centers on a simple stone-lined indoor tub, and a private reservable bath is also available. The spacious tatami rest area is equipped with massage chairs, and the on-site dining area serves local river-fish dishes. Admission is 1,000 yen for adults and 500 yen for children, with hours from 10:30 to 21:00 (closed Tuesdays, though open if a holiday falls on Tuesday, closing the following Wednesday instead). Free parking is available on site.