Bellechasse County, Québec · Water Quality Report Card
Lac Mailloux
Lac Mailloux in Bellechasse, Québec received a water quality grade of B (Good). Water clarity: 2.8 m visibility. Phosphorus: 10.4 µg/L. Chlorophyll-a (algae): 4.9 µg/L.
- Clarity
- 2.8 m
- Type
- Mesotrophic
Lac Mailloux is a mesotrophic lake in Bellechasse County, Québec. Water quality is graded B based on 3 sampling years through 2025. Compared to the 8 other monitored lakes in Bellechasse County, Lac Mailloux ranks #3 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
Moderate clarity, visible to about 9.2 ft. Phosphorus level: 10.4 µg/L. Chlorophyll-a: 4.9 µg/L. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.8 m | C |
| Phosphorus | 10.4 µg/L | A |
| Chlorophyll-a (Algae) | 4.9 µg/L | A |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
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Fishing Lac Mailloux
Location
County Ranking
Ranked #3 of 9 lakes in Bellechasse
Cleaner Lakes Within 30 Miles
Lac Mailloux holds Grade B. 3 nearby lakes hold higher grades.
- ALac CrèVe-FaimBellechasse · 5.7 mi · Higher grade (B → A)
- ALac ChabotLes Etchemins · 16.4 mi · Higher grade (B → A)
- ALac TherrienBellechasse · 10.2 mi · Higher grade (B → A)
Nearby Lakes in Bellechasse
Explore Lac Mailloux 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 Mailloux 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: