La Haute-Côte-Nord County, Québec · Water Quality Report Card
Lac Saint-Onge
Lac Saint-Onge in La Haute-Côte-Nord, Québec received a water quality grade of B (Good). Water clarity: 1.3 m visibility. Phosphorus: 15.3 µg/L. Chlorophyll-a (algae): 5.2 µg/L.
- Clarity
- 1.3 m
- Type
- Mesotrophic
Lac Saint-Onge is a mesotrophic lake in La Haute-Côte-Nord County, Québec. Water quality is graded B based on 3 sampling years through 2025. Compared to the 13 other monitored lakes in La Haute-Côte-Nord County, Lac Saint-Onge ranks #14 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 4.3 ft. Phosphorus level: 15.3 µg/L. Chlorophyll-a: 5.2 µg/L. Trophic State Index: 49.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.3 m | D |
| Phosphorus | 15.3 µg/L | A |
| Chlorophyll-a (Algae) | 5.2 µg/L | B |
| Trophic State Index (TSI) | 49 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Lac Saint-Onge
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Fishing Lac Saint-Onge
Location
County Ranking
Ranked #14 of 14 lakes in La Haute-Côte-Nord
Cleaner Lakes Within 30 Miles
Lac Saint-Onge holds Grade B. 5 nearby lakes hold higher grades.
- ALac GobeilLa Haute-Côte-Nord · 16.7 mi · Higher grade (B → A)
- ALac MaclureLa Haute-Côte-Nord · 18.6 mi · Higher grade (B → A)
- ALac des PiliersLa Haute-Côte-Nord · 11.8 mi · Higher grade (B → A)
- ALac PoletteLa Haute-Côte-Nord · 12.9 mi · Higher grade (B → A)
- ALac des CèDresLa Haute-Côte-Nord · 12.9 mi · Higher grade (B → A)
Nearby Lakes in La Haute-Côte-Nord
Explore Lac Saint-Onge 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 Saint-Onge 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: