Updated August 2026
Safest Lakes to Swim in Québec
Lac Beauport (La Jacques-Cartier County) ranks #1 for swimming in Québec — grade A water with low algae and public access. Below: the top 25 lakes in Québecthat pass our swim-safety filter.
- Grade A–B water quality
- Chlorophyll-a below 10 µg/L
Swimming-friendly is a clarity-plus-algae problem: clear water and a low chlorophyll-a number. Lac Beauport (A) tops the Québec list on those combined measures.
The swimming-best list filters more aggressively on chlorophyll-a than the cleanest list — even very clear lakes can have harmful-algal-bloom risk under specific conditions, so the swimming ranking is more conservative on that front.
| Rank | Lake | County | Grade | Swim Safety | Clarity | Algae | Phosphorus | Area |
|---|---|---|---|---|---|---|---|---|
| 1 | Lac Beauport | La Jacques-Cartier | A | Low algae | 16.7 ft | 2.2 µg/L | 4.7 µg/L | - |
| 2 | Lac Raquette | Beauce-Sartigan | A | Low algae | 19.8 ft | 1.6 µg/L | 5 µg/L | - |
| 3 | Lac des Cornes | Antoine-Labelle | A | Low algae | 20.7 ft | 1.3 µg/L | 3 µg/L | - |
| 4 | Lac PéRodeau | Antoine-Labelle | A | Low algae | 22.3 ft | 1.1 µg/L | 3.1 µg/L | - |
| 5 | Lac Duhamel | Les Laurentides | A | Low algae | 29.2 ft | 0.9 µg/L | 2 µg/L | - |
| 6 | Lac Vert | Papineau | A | Low algae | 26.6 ft | 1.1 µg/L | 3.5 µg/L | - |
| 7 | Lac Farmer | Les Pays-d'en-Haut | A | Low algae | 19 ft | 1.9 µg/L | 4.4 µg/L | - |
| 8 | Lac des Trois Montagnes | Les Laurentides | A | Low algae | 23.6 ft | 1.1 µg/L | 3 µg/L | - |
| 9 | Lac ThéOdore | Les Pays-d'en-Haut | A | Low algae | 16.1 ft | 2.8 µg/L | 5.5 µg/L | - |
| 10 | Lac Ouareau | Matawinie | A | Low algae | 16.7 ft | 2.2 µg/L | 3.2 µg/L | - |
| 11 | Lac Windigo | Les Laurentides | A | Low algae | 18.4 ft | 1.4 µg/L | 3.7 µg/L | - |
| 12 | Lac de la Grange | Les Laurentides | A | Low algae | 20.2 ft | 1.5 µg/L | 3.7 µg/L | - |
| 13 | Lac de la DéCharge | Les Laurentides | A | Low algae | 18.7 ft | 1.3 µg/L | 3.5 µg/L | - |
| 14 | Lac Chevreuil | Les Laurentides | A | Low algae | 23 ft | 1.1 µg/L | 2.8 µg/L | - |
| 15 | Lac Cameron | Les Laurentides | A | Low algae | 21.3 ft | 1.5 µg/L | 3.1 µg/L | - |
| 16 | Lac Rognon | Les Laurentides | A | Low algae | 17.4 ft | 1.4 µg/L | 4 µg/L | - |
| 17 | Lac de la Sucrerie | Les Laurentides | A | Low algae | 15.4 ft | 1.9 µg/L | 3.9 µg/L | - |
| 18 | Petit Lac des CèDres | La Vallée-de-la-Gatineau | A | Low algae | 18.9 ft | 1.3 µg/L | 5.6 µg/L | - |
| 19 | Lac Sauvage | Les Laurentides | A | Low algae | 20.3 ft | 1.1 µg/L | 3.3 µg/L | - |
| 20 | Lac Lesage | Antoine-Labelle | A | Low algae | 22.3 ft | 1.4 µg/L | 3.9 µg/L | - |
| 21 | Lac SupéRieur | Les Laurentides | A | Low algae | 16.4 ft | 2.2 µg/L | 4.9 µg/L | - |
| 22 | Lac ÉQuerre | Les Laurentides | A | Low algae | 16.7 ft | 2.5 µg/L | 4 µg/L | - |
| 23 | Lac Gauthier | Les Laurentides | A | Low algae | 20.5 ft | 1.1 µg/L | 3.7 µg/L | - |
| 24 | Lac Blue Sea | La Vallée-de-la-Gatineau | A | Low algae | 21.3 ft | 1.1 µg/L | 4.6 µg/L | - |
| 25 | Lac Paquin | La Vallée-de-la-Gatineau | A | Low algae | 30.8 ft | 0.6 µg/L | 3.1 µg/L | - |
Frequently Asked Questions
What is the best lake to swim in Québec?
Lac Beauport in La Jacques-Cartier County ranks #1 for swimming-safety in our 2026 Québec dataset, combining grade-A water clarity with low algae and public access. The full top 25 above ranks the swim-safest lakes statewide.
How do you know if a lake is safe to swim in Québec?
Three signals: (1) water clarity — Secchi depth above 6 feet is a strong sign of low suspended sediment and pathogens; (2) chlorophyll-a below 10 µg/L means low risk of harmful algae bloom; (3) a current grade of A or B from year-round sampling. MELCCFP and county health departments post seasonal advisories — always check before you swim, especially in late summer when blue-green algae bloom risk peaks.
Are lakes in Québec safe to swim in?
Most monitored Québec lakes are safe to swim in under normal conditions, but water quality varies widely. The lakes ranked above are filtered to grade A and B with chlorophyll-a below 10 µg/L — meaning they consistently test cleaner and have lower algae bloom risk than the state average. Always check posted advisories before swimming and avoid water after heavy rain (bacterial contamination spikes from runoff).
What lakes have algae blooms in Québec?
Algae blooms (especially blue-green / cyanobacteria) are most common in shallow, warm, nutrient-rich (eutrophic) lakes during late summer. Lakes with high phosphorus and chlorophyll-a measurements are at higher risk. The lakes on this page are filtered to exclude high-algae lakes. For the opposite list, see our most-polluted-lakes trend page.
When is it safe to swim in lakes in Québec?
Québec lakes are typically safest to swim in late spring through early summer (May–July), when water is cool and algae bloom risk is lowest. Risk rises in late summer and early fall (August–September) when warm water and accumulated nutrients drive cyanobacteria blooms. Always avoid swimming after heavy rainfall (bacterial spikes from runoff) and check current state DNR advisories the day you go.
What's the cleanest lake in Québec?
The single cleanest lake by combined water-quality score is featured on the Québec cleanest-lakes page. The lakes here are filtered specifically for swimming safety — same A/B grade requirement, plus low chlorophyll-a (active algae filter). For the broader cleanliness ranking, see /best/cleanest/qc.
Our swimming-safety filter
We don't just rank by overall grade. Lakes here have to pass three filters:
- Grade A or B overall water quality (top 40% statewide)
- Chlorophyll-a below 10 µg/L — actively low algae density, low risk of harmful blue-green blooms
- Multi-year sampling data — excludes lakes with limited sampling history (data confidence)
The Swim Safety column adds a direct bacteria signal on top of the grade: where the EPA Water Quality Portal has enough E. coli or fecal-coliform samples, we show a historical swim-safety grade (how often the lake has exceeded the safe-swimming threshold). It is a record of past testing, never a live "safe today" reading — bacteria spike fast after rain.
The ranking within the filter is by combined water-quality score (Secchi clarity + phosphorus + chlorophyll-a). Always check current MELCCFP advisories before swimming.
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Source: EPA National Aquatic Resource Surveys, 2026.