Skip to main content
LakeQuality

Lake water quality in Japan

Japan has 188 named lakes in this catalog, sampled 2021–2025. 188 have total phosphorus, 159 have Secchi depth. Values are the authority's measurements, not a LakeQuality letter grade.

Lake map

Loading map…

Places in Japan

Named lakes

LakePlaceTotal phosphorusChlorophyll-aSecchiYear
ます渕ダムFukuoka7.0 µg/L3.5 m2025
みどり湖Nagano26 µg/L2024
七ケ宿ダムMiyagi8.0 µg/L3.2 m2025
七北田ダムMiyagi19 µg/L2024
三川ダム貯水池Hiroshima35 µg/L2.3 m2025
三方五湖Fukui45 µg/L1.3 m2025
下久保ダム貯水池Gunma14 µg/L3.0 m2025
下久保ダム貯水池Saitama14 µg/L3.0 m2025
世増ダム貯水池Aomori33 µg/L2.4 m2025
世増ダム貯水池Iwate59 µg/L1.8 m2024
中禅寺湖Tochigi5.0 µg/L7.8 m2024
中綱湖Nagano9.0 µg/L2024
丹沢湖Kanagawa8.0 µg/L4.0 m2025
亀山ダム貯水池Chiba38 µg/L1.3 m2025
二ノ目潟Akita11 µg/L5.0 m2024
二瀬ダム貯水池Saitama11 µg/L0.8 m2025
伊豆沼Miyagi98 µg/L2024
佐久間ダム貯水池Shizuoka34 µg/L1.6 m2025
佐幌ダム貯水池Hokkaido10 µg/L3.7 m2024
佐鳴湖Shizuoka140 µg/L0.4 m2025
倶多楽湖Hokkaido3.0 µg/L17 m2024
児島湖Okayama185 µg/L0.6 m2025
入畑ダム貯水池Iwate9.0 µg/L2.4 m2025
八田原ダム貯水池Hiroshima25 µg/L2.3 m2025
八郎湖Akita84 µg/L0.6 m2025
力丸ダムFukuoka17 µg/L3.0 m2025
北山ダムSaga28 µg/L2.0 m2025
北川ダムOita11 µg/L3.5 m2025
北潟湖Ishikawa57 µg/L0.6 m2025
北潟湖Fukui78 µg/L0.8 m2025
十和田湖Aomori4.0 µg/L10 m2024
十和田湖Akita4.0 µg/L11 m2024
千五沢ダム貯水池Fukushima50 µg/L1.2 m2024
千苅水源池Hyogo26 µg/L2.3 m2025
南川ダムMiyagi15 µg/L2024
印旛沼Chiba130 µg/L0.4 m2025
味噌川ダム貯水池Nagano7.0 µg/L8.6 m2025
四十四田ダム貯水池Iwate26 µg/L2.1 m2025
土師ダム貯水池Hiroshima19 µg/L0.6 m2025
坂本ダム湖Nara9.0 µg/L2024
境川ダム貯水池Toyama3.0 µg/L5.1 m2024
境川ダム貯水池Gifu3.0 µg/L5.1 m2024
夏瀬ダムAkita6.0 µg/L5.0 m2024
大倉ダムMiyagi8.0 µg/L2024
大原湖Yamaguchi8.0 µg/L4.4 m2025
大川ダム貯水池Fukushima11 µg/L2.8 m2025
大座法師池Nagano16 µg/L2024
大橋ダム貯水池Kochi4.0 µg/L2024
大迫ダム湖Nara10 µg/L2024
奈良俣ダム貯水池Gunma4.0 µg/L5.5 m2024
奥只見貯水池Fukushima6.0 µg/L5.6 m2024
奥只見貯水池Niigata5.0 µg/L6.0 m2024
女神湖Nagano14 µg/L2024
宍道湖Shimane45 µg/L1.5 m2025
室生ダム湖Nara32 µg/L2.7 m2024
宮ヶ瀬湖Kanagawa6.0 µg/L5.2 m2025
寒河江ダム貯水池Yamagata10 µg/L1.5 m2024
寺内ダムFukuoka31 µg/L1.6 m2025
小川原湖Aomori33 µg/L1.4 m2025
小河内貯水池Tokyo8.0 µg/L6.5 m2025
小瀬川ダム貯水池Hiroshima11 µg/L2.6 m2025
小野川湖Fukushima7.0 µg/L2.7 m2024
小野湖Yamaguchi22 µg/L2.5 m2025
尾瀬沼Gunma6.0 µg/L3.7 m2024
尾瀬沼Fukushima10 µg/L3.5 m2024
屈斜路湖Hokkaido6.0 µg/L8.3 m2024
山中湖Yamanashi10 µg/L4.4 m2025
山代湖Yamaguchi14 µg/L3.6 m2025
岩洞ダム貯水池Iwate9.0 µg/L3.4 m2024
岩見ダムAkita14 µg/L2.4 m2024
川俣ダム貯水池Tochigi7.0 µg/L6.1 m2025
川治ダム貯水池Tochigi8.0 µg/L4.5 m2025
市房ダム貯水池Kumamoto15 µg/L1.1 m2025
布目ダム湖Nara36 µg/L2.5 m2024
帝釈川ダム貯水池Hiroshima20 µg/L2.3 m2025
常盤湖Yamaguchi20 µg/L2.0 m2025
弥栄ダム貯水池Hiroshima8.0 µg/L5.8 m2025
弥栄湖Yamaguchi8.5 µg/L5.8 m2025
御所ダム貯水池Iwate10 µg/L2.5 m2025
徳山ダム貯水池Gifu4.5 µg/L2024

Showing 80 of 188 named lakes. Open a county or place page for the rest.

Where to stay near Japan

Lakeside cabins, hotels, and vacation rentals near Japan — live availability from Booking.com, Vrbo and Expedia.

Top-rated places to stay near Japan

Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.

Planning a trip to Japan?

Get lake water-quality report cards plus the best cabin & lodging deals near Japan — straight to your inbox. No spam, unsubscribe anytime.

Official surface phosphorus, chlorophyll-a, and/or Secchi. Not a LakeQuality A–F grade — the authority does not publish a letter on this scale.

Monitoring: the Ministry of the Environment (Japan).