Totsukawa Onsen Iori-no-Yu is a village-operated public bathhouse located on the shore of Futatsuno Dam Lake in Hiradani, Totsukawa Village, Yoshino District, Nara Prefecture. Opened in June 2005, it drew widespread attention as the first hot spring facility in Nara Prefecture to feature both a drinking fountain and a foot bath. Totsukawa Village was a national pioneer in 2004 when it became the first municipality in Japan to issue a 'Source Water Free-Flowing Declaration,' pledging that all hot spring facilities in the village -- including Iori-no-Yu -- would provide genuine onsen water without any circulation, reuse, heating, dilution, or chlorine disinfection.

The spring water is classified as a sodium bicarbonate and chloride spring with a source temperature of 70 degrees Celsius and a mildly alkaline pH of 7.9. The high-temperature source water is naturally cooled to a comfortable bathing temperature and delivered as 100 percent free-flowing source water. Upon entering the bathing room, one is greeted by a rich aroma of sulfur and iron, and the water has a notably soft, skin-moisturizing quality. The spring is reputed to be effective for cuts, sensitivity to cold, and burns.

In addition to separate indoor baths for men and women, the facility offers foot and hand baths overlooking Futatsuno Dam Lake, Nara Prefecture's first drinking spring fountain, and a rest area with benches. From the bathing room windows, visitors can enjoy a panoramic view of the emerald-green waters of Futatsuno Lake and the surrounding mountains, with natural beauty that shifts with the seasons. Directly connected to the Totsukawa Onsen bus terminal, the facility is conveniently accessible by public transportation.