Kamioka Onsen Hozanso
Analysis UnverifiedKamioka Onsen flows on its own, without pumps, from a 170 m well drilled in 1957 in Beppu's Kannawa district. A 2025 analysis recorded 89.5°C and pH 9.0: an unusual alkaline sulfur spring in a town known for acidic sulfur waters, its sulfur dissolved as hydrosulfide ions rather than gas. Sodium 228.0 mg/kg, bicarbonate 279.0 mg/kg, sulfate 184.0 mg/kg and metasilicic acid 339.0 mg/kg give a clear water with a faint sulfur scent and a quiet, deeply comforting character.
The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).
A natural moisturizer also used in skincare lotions. Forms a thin veil on the skin to reduce moisture loss after bathing.
Scores are calculated from mineral analysis data based on the Mineral Spring Analysis Guidelines (Ministry of Environment, Japan). They are unrelated to facility atmosphere or service quality.
▸Note
The temperature, pH and component values shown here are based on the hot spring analysis (source). Actual values in the bath may differ depending on heating, dilution, recycling and filtration. Please check current usage status at the facility.
The source emerges at 89.5°C, so never touch the inflow and check the bath temperature first. At pH 9.0 the water leaves skin very smooth; rinse lightly and moisturize afterward.
With pH 9.0, 279.0 mg/kg of bicarbonate and 339.0 mg/kg of metasilicic acid, the water may support silky skin, while its dissolved sulfur is traditionally associated with immune system stimulation.
The source is 89.5°C, so beware of scalding near the inflow. Sulfur can tarnish metal jewelry; remove accessories. Avoid bathing when unwell or after drinking.
※ See the analysis data below for detailed contraindications
ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- Kamioka Onsen Hozanso
- Spring type
- Sulfur-containing Sodium Bicarbonate and Sulfate Hot Spring
- Old spring type name
- 含重曹芒硝-硫黄泉
- Source temperature
- 89.5℃
- pH
- 9
- Flow type
- 掘削自噴
- Osmotic pressure
- 低張性
Analysis Document
- Analysis date
- 2025-10-30
- Analyst organization
- 公益社団法人大分県薬剤師会 検査センター
- Registration No.
- 大分県第3号
Cations
- Lithium ion Li⁺
- 0.40 mg/kg
- Sodium ion Na⁺
- 228 mg/kg
- Potassium ion K⁺
- 14.7 mg/kg
- Calcium ion Ca²⁺
- 1.0 mg/kg
- Aluminum ion Al³⁺
- 0.30 mg/kg
- Lead ion Pb²⁺
- < 0.01 mg/kg
- Copper ion Cu²⁺
- < 0.05 mg/kg
- Cadmium ion Cd²⁺
- < 0.001 mg/kg
- Total cations
- 0.24 mg/kg
Anions
- Fluoride ion F⁻
- 0.80 mg/kg
- Chloride ion Cl⁻
- 10.8 mg/kg
- Hydroxide ion OH⁻
- 0.20 mg/kg
- Hydrogen sulfide ion HS⁻
- 2.6 mg/kg
- Thiosulfate ion S₂O₃²⁻
- 1.0 mg/kg
- Sulfate ion SO₄²⁻
- 184 mg/kg
- Bicarbonate ion HCO₃⁻
- 279 mg/kg
- Carbonate ion CO₃²⁻
- 58.9 mg/kg
- Total anions
- 0.54 mg/kg
Undissociated Components
- Sulfuric acid H₂SO₄
- 0.00 mg/kg
- Phosphoric acid H₃PO₄
- 0.00 mg/kg
- Arsenious acid HAsO₂
- 0.00 mg/kg
- Metasilicic acid H₂SiO₃
- 339 mg/kg
- Metaboric acid HBO₂
- 1.2 mg/kg
- Total undissociated
- 0.34 mg/kg
Dissolved Gas
- Free carbon dioxide CO₂
- 0.00 mg/kg
- Free hydrogen sulfide H₂S
- 0.00 mg/kg
- Total dissolved gas
- 0.00 mg/kg
Trace Components
- Radon Rn
- < 7.4 Bq/kg
Totals
- Total dissolved substances
- 1.1 mg/kg
- Component total
- 1.1 mg/kg
- Evaporation residue
- 0.90 mg/kg
Usage
- Usage status
- Unknown
Indications & Contraindications
- Bathing indications
- Atopic dermatitis, Plaque psoriasis, Chronic eczema, Epidermal suppuration, Cuts and grazes, Peripheral circulatory failure, Poor circulation, Xeroderma, Depression
- General indications
- High blood pressure (mild), Rheumatoid arthritis, Autonomic instability, Insomnia, Chronic pain or stiffness in muscles and joints, Muscle stiffness due to motor paralysis, Gastrointestinal dysfunction
- Contraindications
- Acute illness (especially with fever), Active tuberculosis, Malignant tumors, Severe heart disease, Respiratory failure, Renal failure, Bleeding disorders, Severe anemia, Any actively progressing illness, Pregnancy (especially early and late stages), Severe chronic dermatitis (sulphur springs)
Drinking
- Drinkability
- Not drinkable
