Yumotokan, Imaita Onsen (Day Use)

Spring-source temperature

20.6°C in the current Gozu Onsenkyo association listing; the inn's multilingual page also retains 20.3°C, so both describe a low-temperature source rather than a bath temperature

Bathing temperature

About 40–41°C after circulation and heating, according to the inn's current FAQ; operating target rather than a guaranteed fixed value

Spring source

Imaita Onsen natural radon spring; the current association listing describes Yumotokan as the sole inn at the source, but no individual well number is confirmed

Spring classification

Simple weak radioactive cold mineral spring (radium spring; alkaline, low-tonicity, low-mineral spring)

pH

7.5 in the current Gozu Onsenkyo association listing

Flow rate

103 L/min in the current Gozu Onsenkyo association listing

Water handling

The inn says the bath uses 100% source water with no added water, but explicitly says it is not free-flowing. The low-temperature source is circulated and heated; both indoor and outdoor baths use the spring. Drinking the water is not permitted because there is no drinking-water authorization.

Adult admission is ¥800 from April 1, 2026. Day use runs 10:30–15:00 and 18:00–21:00, but closures, cleaning and crowding may interrupt access. Check the monthly schedule. The baths are not fully step-free; there are about four steps to the outdoor bath. Drinking the water is not permitted. Tattoo rules are unconfirmed.