Les Pays-d'en-Haut County, Québec · Water Quality Report Card
Lac Saint-Denis
Lac Saint-Denis in Les Pays-d'en-Haut, Québec received a water quality grade of A (Excellent). Water clarity: 6.3 m visibility. Phosphorus: 2.7 µg/L. Chlorophyll-a (algae): 1.5 µg/L.
- Clarity
- 6.3 m
- Type
- Oligotrophic
Lac Saint-Denis is a cold, clear oligotrophic lake in Les Pays-d'en-Haut County, Québec. Water quality is graded A based on 3 sampling years through 2025. Compared to the 108 other monitored lakes in Les Pays-d'en-Haut County, Lac Saint-Denis ranks #17 for water quality.
Source: EPA Water Quality Portal sampling records, MELCCFP, last sampled 2025-08-01. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Crystal clear, you can see 20.5 ft down. Phosphorus level: 2.7 µg/L. Chlorophyll-a: 1.5 µg/L. Trophic State Index: 29.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.25 m | A |
| Phosphorus | 2.7 µg/L | A |
| Chlorophyll-a (Algae) | 1.5 µg/L | A |
| Trophic State Index (TSI) | 29 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Lac Saint-Denis
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Fishing Lac Saint-Denis
Location
County Ranking
Ranked #17 of 109 lakes in Les Pays-d'en-Haut
Nearby Lakes in Les Pays-d'en-Haut
Explore Lac Saint-Denis across LakeGrade
More Québec Lake Rankings
Other Grade A Lakes in Québec
Oligotrophic Lakes in Québec
More records, surveys & data sources
Where this data comes from
Measurements for Lac Saint-Denis come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.
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: 2025-08-01
Monitoring stations: