Clearest lakes in France
Clearest lakes in France: 307 named lakes have an official Secchi depth. The 20 below are ranked by that reading, water clarity as the authority reports it.
Lake map
Map shows 20 lakes with coordinates
Highest Secchi readings in France
| Lake | Place | Total phosphorus | Chlorophyll-a | Secchi | Year |
|---|---|---|---|---|---|
| Lac Bleu | Hautes-Pyrénées | — | 1.0 µg/L | 15 m | 2022 |
| Lac de Migouélou | Hautes-Pyrénées | — | 1.0 µg/L | 12 m | 2022 |
| Lac de Caillauas | Hautes-Pyrénées | — | 1.0 µg/L | 11 m | 2020 |
| Lac de L'Oule | Hautes-Pyrénées | — | 1.0 µg/L | 11 m | 2020 |
| Etang de Soulcem | Ariège | — | 1.0 µg/L | 10 m | 2024 |
| Lac de Cap de Long | Hautes-Pyrénées | — | 1.0 µg/L | 9.8 m | 2024 |
| Etang de Naguilhes | Ariège | — | 1.0 µg/L | 9.3 m | 2023 |
| Lac D'Orédon | Hautes-Pyrénées | — | 1.0 µg/L | 8.9 m | 2023 |
| Lac de Servieres | Puy-de-Dôme | — | 1.2 µg/L | 8.4 m | 2022 |
| Lac D'Arjuzanx | Landes | 10 µg/L | 0.60 µg/L | 8.3 m | 2023 |
| Lac D'Aubert | Hautes-Pyrénées | — | 1.0 µg/L | 7.8 m | 2021 |
| Etang de Gnioure | Ariège | — | 1.0 µg/L | 7.7 m | 2024 |
| Lac du Bouchet | Haute-Loire | — | 1.2 µg/L | 7.2 m | 2023 |
| Lac de Tazenat | Puy-de-Dôme | 10 µg/L | 2.1 µg/L | 7.1 m | 2023 |
| Lac de Sède | Haute-Garonne | — | 1.5 µg/L | 5.8 m | 2022 |
| Le Lac de Kruth-Wildenstein | Haut-Rhin | — | 1.0 µg/L | 5.2 m | 2021 |
| Barrage-Réservoir Seine | Aube | — | 2.0 µg/L | 5.0 m | 2024 |
| Le Lac de Longemer | Vosges | — | 2.5 µg/L | 5.0 m | 2017 |
| Lac de Commanday | Landes | 10 µg/L | 0.60 µg/L | 5.0 m | 2020 |
| Lac D'Issarles | Ardèche | 10 µg/L | 6.0 µg/L | 4.9 m | 2025 |
Showing 20 of 307 named lakes. Open a county or place page for the rest.
Frequently asked questions
- Which lakes in France are the clearest?
- 307 named lakes in France have an official Secchi depth. This page ranks the 20 deepest readings. Secchi is a clarity measurement, not a swim-safety class.
- Is clear water the same as clean water?
- No. Secchi measures how far a disk stays visible. A clear lake can still have bacteria, toxins, or contaminants this catalog does not measure. Open a lake page for the authority's values.
Clearest lakes in other countries
Named lakes and official measurements
Directory of official lake water quality
3,904 lakes with Secchi
748 lakes with Secchi
409 lakes with Secchi
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Where to stay near France
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