Natural alkaline hot spring water ZAIHO ONSEN is drinkable hot spring water pumped from 1,000m underground of Tarumizu city located at the foot of Sakurajima in Kagoshima Prefecture. Mineral water in Japan is mostly soft water but ZAIHO is ultra-soft with a hardness level of mere 4mg/L, so it is mild and slightly sweet, which tastes good even at room temperature. In addition, ZAIHO water is also healthy as it is mildly alkaline (pH8.9).