Les Laurentides County, Québec · Water Quality Report Card
Lac Gagnon
Lac Gagnon in Les Laurentides, Québec received a water quality grade of B (Good). Water clarity: 1.8 m visibility. Phosphorus: 8.6 µg/L. Chlorophyll-a (algae): 1.9 µg/L.
- Clarity
- 1.8 m
- Type
- Mesotrophic
Lac Gagnon is a mesotrophic lake in Les Laurentides County, Québec. Water quality is graded B based on 3 sampling years through 2025. Compared to the 118 other monitored lakes in Les Laurentides County, Lac Gagnon ranks #102 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
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Murky, only visible to about 5.7 ft. Phosphorus level: 8.6 µg/L. Chlorophyll-a: 1.9 µg/L. Trophic State Index: 41.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.75 m | D |
| Phosphorus | 8.6 µg/L | A |
| Chlorophyll-a (Algae) | 1.9 µg/L | A |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
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Fishing Lac Gagnon
Location
County Ranking
Ranked #102 of 119 lakes in Les Laurentides
Cleaner Lakes Within 30 Miles
Lac Gagnon holds Grade B. 5 nearby lakes hold higher grades.
- ALac JosephLes Laurentides · 1.1 mi · Higher grade (B → A)
- ALac GodonLes Laurentides · 2.8 mi · Higher grade (B → A)
- ALac QuenouilleLes Laurentides · 1.6 mi · Higher grade (B → A)
- BLac PapineauLes Laurentides · 2.8 mi · Higher overall water quality score
- BLac DesforgesLes Laurentides · 2.8 mi · Higher overall water quality score
Nearby Lakes in Les Laurentides
Explore Lac Gagnon across LakeGrade
More Québec Lake Rankings
Other Grade B Lakes in Québec
Mesotrophic Lakes in Québec
More records, surveys & data sources
Where this data comes from
Measurements for Lac Gagnon 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: