Le Granit County, Québec · Water Quality Report Card
Lac Thor
Lac Thor in Le Granit, Québec received a water quality grade of B (Good). Water clarity: 4.4 m visibility. Phosphorus: 7 µg/L. Chlorophyll-a (algae): 5 µg/L.
- Clarity
- 4.4 m
- Type
- Oligotrophic
Lac Thor is a cold, clear oligotrophic lake in Le Granit County, Québec. Water quality is graded B based on 3 sampling years through 2025. Compared to the 9 other monitored lakes in Le Granit County, Lac Thor ranks #7 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
Good clarity, visible to about 14.4 ft. Phosphorus level: 7 µg/L. Chlorophyll-a: 5 µg/L. Trophic State Index: 39.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.4 m | B |
| Phosphorus | 7 µg/L | A |
| Chlorophyll-a (Algae) | 5 µg/L | B |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Lac Thor
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Fishing Lac Thor
Location
County Ranking
Ranked #7 of 10 lakes in Le Granit
Cleaner Lakes Within 30 Miles
Lac Thor holds Grade B. 4 nearby lakes hold higher grades.
- ALac ÉQuerreLe Granit · 2.8 mi · Higher grade (B → A)
- ALac ElginLe Granit · 5.4 mi · Higher grade (B → A)
- ALac RuelLe Granit · 5.6 mi · Higher grade (B → A)
- APetit Lac LambtonLe Granit · 9.9 mi · Higher grade (B → A)
Nearby Lakes in Le Granit
Explore Lac Thor across LakeGrade
More Québec Lake Rankings
Other Grade B Lakes in Québec
Oligotrophic Lakes in Québec
More records, surveys & data sources
Where this data comes from
Measurements for Lac Thor 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: