Owakudani Onsen Steam-induced Mixed Spring

Analysis Verified
大涌谷温泉 蒸気造成混合泉
Owakudani's Earthly Pulse

Originating from the fumaroles of Owakudani, born from the eruption of Hakone volcano approximately 3,000 years ago, this artificially developed hot spring began to be supplied to Sengokuhara and Gora by Hakone Onsen Kyokyu Co., Ltd. in Showa 5 (1930). Its renowned milky white waters, blended with naturally gushing spring water, offer a pleasant sensation that tightens the skin and a powerful restorative warmth that penetrates deep into the body's core. After bathing, you'll feel surprisingly refreshed and light. It's a perfect companion when you seek to feel the Earth's energy and achieve deep relaxation and rejuvenation for your mind and body.

AI Generated
This source matches 3 spring types· Tap to switch
SPRING TYPE
Acidic Spring

These springs have a strong antibacterial effect which can result in a mild tingling sensation on contact. Effective for healing wounds and relieving inflammatory skin conditions. Those with sensitive skin should rinse with fresh water after bathing.

See features & indications
Bathing indications
Atopic dermatitisPlaque psoriasisEpidermal suppurationImpaired glucose tolerance (diabetes)
Cautions
  • 皮膚または粘膜の敏感な方、高齢者の皮膚乾燥症の方は禁忌です。
  • 肌が弱い方は入浴後に真湯で洗い流してください。
Definition :Contains 1 mg/kg or more of hydrogen ions.
Source: 環境省「あんしん・あんぜんな温泉利用のいろは」(監修:日本温泉気候物理医学会)Read full article
PH VALUE
2.1
Acidic
Acidic ← 07 Neutral14 → Alkaline
Acidic spring (pH < 3). Antibacterial and skin-softening effects. Known for a refreshing bathing experience.
Caution: Avoid prolonged bathing. Rinse with fresh water after bathing. Not recommended for those with open wounds.
TEMPERATURE
60.6
Very Hot Spring
Very hot. Cannot be bathed in without significant dilution.
KEY MINERALS

The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).

Aluminum ionSee detail
7.5 mg/kg

Tightens the skin and balances sebum.

Metasilicic acidSee detail
157 mg/kg

A natural moisturizer also used in skincare lotions. Forms a thin veil on the skin to reduce moisture loss after bathing.

Metaboric acidSee detail
14.2 mg/kg

A trace component with gentle antibacterial and anti-inflammatory action.

Iron(II) ionSee detail
13.2 mg/kg

Iron content that boosts heat retention and may tint the water.

Free hydrogen sulfideSee detail
1.3 mg/kg

The aroma typical of sulfur springs, with circulatory and antibacterial effects.

CHARACTER · COMPOSITION PROFILE
1234StimulationBactericidalSkin BeautyHeat RetentionRelaxation

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.

USAGE
Free-Flowing Onsen
Pure spring water — no dilution, no recirculation
HeatedNo
DilutedNo
RecycledNo
FilteredNo
DisinfectedNo
AdditivesNo
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.

SENSORY TEST
Color
微白濁
Smell
微硫化水素臭
EFFECTS
Spring-specific indications (bathing)
Atopic dermatitisXerodermaChronic pain or stiffness in muscles and jointsCuts and grazesPeripheral circulatory failurePoor circulationGastrointestinal dysfunctionHigh blood pressure (mild)Impaired glucose tolerance (diabetes)DyslipidemiaMild asthma or emphysemaHemorrhoidsAutonomic instabilityStress-related symptoms (insomniadepressionetc.)Recovery from illnessFatigue recoveryHealth promotion
Contraindications
Active stages of illness (especially with fever)Active tuberculosisAdvanced malignant tumors or severe anemia causing significant weaknessSevere heart or lung disease causing shortness of breath with slight movementSevere kidney disease with swellingGastrointestinal bleedingVisible bleedingAcute exacerbation of chronic illnessPeople with sensitive skin or mucous membranes
BATHING TIPS
AI Generated

With a very strong acidity of pH 2.1, those with sensitive skin should be cautious. To prevent overheating, avoid long soaks and it is recommended to rinse off the spring water with a shower after bathing. Be careful not to get it in your eyes.

EFFECT STORY
AI Generated

This potent acidic spring, with a pH of 2.1, has long been used for balneotherapy. Its sterilizing properties are associated with improving skin issues, traditionally seen as a way to support immune system stimulation. As a sulfate spring, it may also help relieve pain from cuts and joints. The high metasilicic acid content of 157 mg/kg is also said to promote skin metabolism.

CAUTIONS
AI Generated

Due to its very high acidity, individuals with sensitive skin or mucous membranes should bathe with caution. It can cause strong irritation if it gets in your eyes. Please refrain from bathing if you have general contraindications such as acute illness or severe heart disease.

※ See the analysis data below for detailed contraindications

ANALYSIS DATAView all analysis fields ▼

Source Info

Source name
Owakudani Onsen Steam-induced Mixed Spring
Spring type
Acidic Calcium Sulfate and Chloride Hot Spring
Old spring type name
酸性-含塩化土類-石膏泉
Source temperature
60.6℃
pH
2.1
Flow type
造成温泉(蒸気造成混合泉)
Osmotic pressure
低張性

Analysis Document

Analysis date
2018-09-28
Analyst organization
神奈川県温泉地学研究所
Registration No.
神奈川県知事登録第1号

Cations

Hydrogen ion H⁺
8.0 mg/kg
Lithium ion Li⁺
0.00 mg/kg
Sodium ion Na⁺
40.5 mg/kg
Potassium ion K⁺
3.2 mg/kg
Ammonium ion NH₄⁺
0.22 mg/kg
Magnesium ion Mg²⁺
34.7 mg/kg
Calcium ion Ca²⁺
90.6 mg/kg
Aluminum ion Al³⁺
7.5 mg/kg
Manganese ion Mn²⁺
1.3 mg/kg
Iron(II) ion Fe²⁺
13.2 mg/kg
Zinc ion Zn²⁺
0.04 mg/kg
Lead ion Pb²⁺
0.02 mg/kg
Strontium ion Sr²⁺
0.17 mg/kg
Copper ion Cu²⁺
0.00 mg/kg
Cadmium ion Cd²⁺
0.00 mg/kg
Total cations
0.20 mg/kg

Anions

Fluoride ion F⁻
0.80 mg/kg
Chloride ion Cl⁻
342 mg/kg
Sulfate ion SO₄²⁻
443 mg/kg
Bromide ion Br⁻
0.14 mg/kg
Hydrogen sulfate HSO₄⁻
118 mg/kg
Nitrate ion NO₃⁻
0.49 mg/kg
Total anions
0.90 mg/kg

Undissociated Components

Sulfuric acid H₂SO₄
2.4 mg/kg
Metasilicic acid H₂SiO₃
157 mg/kg
Metaboric acid HBO₂
14.2 mg/kg
Total undissociated
0.17 mg/kg

Dissolved Gas

Free hydrogen sulfide H₂S
1.3 mg/kg

Totals

Component total
1.3 mg/kg
Evaporation residue
1.2 mg/kg

Usage

Heating
No
Dilution
No
Recycle / Filter
No
Additives
No
Disinfection
No

Indications & Contraindications

Bathing indications
Atopic dermatitis, Xeroderma, Chronic pain or stiffness in muscles and joints, Cuts and grazes, Peripheral circulatory failure, Poor circulation, Gastrointestinal dysfunction, High blood pressure (mild), Impaired glucose tolerance (diabetes), Dyslipidemia, Mild asthma or emphysema, Hemorrhoids, Autonomic instability, Stress-related symptoms (insomnia, depression, etc.), Recovery from illness, Fatigue recovery, Health promotion
Contraindications
Active stages of illness (especially with fever), Active tuberculosis, Advanced malignant tumors or severe anemia causing significant weakness, Severe heart or lung disease causing shortness of breath with slight movement, Severe kidney disease with swelling, Gastrointestinal bleeding, Visible bleeding, Acute exacerbation of chronic illness, People with sensitive skin or mucous membranes

Drinking

Drinkability
Not drinkable
FACILITY INFO
Official site
Private bath (Kashikiri)
Available
Room with private open-air bath
Available
About tattoos and onsen
Travelers with tattoos can still bathe comfortably in a private bath (Kashikiri) or a room with a private open-air bath.
Hours
Weekdays: 00:0024:00
Weekends & holidays: 00:0024:00
Public baths are available 24 hours. Private open-air baths are available from 5:00 to 24:00.
Closed days: Open all year round
Transit
From Hakone-Yumoto Station (箱根湯本駅), take the Hakone Tozan Bus (for Togendai (桃源台)) for approx. 25-30 minutes, get off at 'Sengokuro-mae' (仙郷楼前) bus stop. Approx. 15-20 minutes by car from Tomei Gotemba IC (東名御殿場IC).
Parking
Available, 80 spaces, Free
Facilities
Public BathOpen-air BathPrivate BathIn-room Open-air BathGift ShopVending MachinesBanquet HallConference Room
House rules
Mixed-gender bathing in the public bath is restricted for individuals aged 7 and above, according to Kanagawa Prefecture (神奈川県) ordinance.
This information may change without notice. Please contact the facility directly for accurate details.
Last updated: 6/1/2026
How Long to Stay (Toji)
Start with 2 nights / 3 days

Japan’s Ministry of the Environment notes that even a short stay refreshes you. For a full therapeutic cure, around 2–3 weeks is the guideline.

More on toji length
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The descriptions, catch phrases, and translations on this page are generated by AI (Claude). pH, temperature, and component values are OCR-extracted from the official analysis report. Learn more