河口湖
河口湖 in Yamanashi, Japan has official water-quality measurements, not a LakeQuality A–F grade. Water clarity: 3.5 m visibility. Phosphorus: 12 µg/L.
- Clarity
- 3.5 m
Why 河口湖 has no A–F grade
河口湖 in Japan is published with the authority's own measurements, not a LakeQuality letter. official authority class; not a LakeQuality A–F letter Sampling here has recorded water clarity and phosphorus, but not algae (chlorophyll-a).
A letter on the LakeQuality scale would be an invention, not an official class. Everything below that has been measured is still reported on this page.
Monitoring: the Ministry of the Environment (Japan).
河口湖 is a lake in Yamanashi County, Japan.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-03-15. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for 河口湖
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Good clarity, visible to about 11.5 ft. Phosphorus level: 12 µg/L. Trophic State Index: 41.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.5 m | Not graded |
| Phosphorus | 12 µg/L | Not graded |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near 河口湖
Compare lakeside cabins, hotels, and vacation rentals near 河口湖 in Yamanashi, Japan — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
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Fishing 河口湖
Frequently asked questions about 河口湖
What is the water quality of 河口湖?
- 河口湖 in Yamanashi, Japan has official water-quality measurements, not a LakeQuality A–F grade. Water clarity: 3.5 m visibility. Phosphorus: 12 µg/L.
Is 河口湖 safe to swim in?
- 河口湖 has official nutrient and clarity measurements, not a bacteria swim class and not a safety clearance. Algal blooms, currents, and depth are not covered. Always check local notices before swimming.
Explore 河口湖 across LakeGrade
More lakes in Japan
Where this data comes from
90 measurements from 2 monitoring stations, 2016–2025. Retrieved from Japan MOE public water-body monitoring (not the EPA Water Quality Portal) on 2026-08-16.
Collected and reported by
- Ministry of the Environment (Japan)
moe-jp90 samples · 2016–2025
Analytical methods
- MOE public water body monitoring (kosui, lakes)
Monitoring station identifiers (2)
19200201920030
Authority classifications are stored separately from LakeQuality A–F letters and are never blended. See methodology and data sources.
Data Sources
Water quality data from the EPA Water Quality Portal
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion
Most recent sample: 2025-03-15
Monitoring stations: 2