Leeds and Grenville Counties County, Ontario · Water Quality Report Card
Red Horse Lake
Red Horse Lake in Leeds and Grenville Counties, Ontario received a water quality grade of A (Excellent). Water clarity: 4 m visibility. Phosphorus: 17.6 µg/L.
- Clarity
- 4 m
- Type
- Mesotrophic
Red Horse Lake is a mesotrophic lake in Leeds and Grenville Counties County, Ontario. Water quality is graded A based on 2 sampling years through 2025. Compared to the 33 other monitored lakes in Leeds and Grenville Counties County, Red Horse Lake ranks #19 for water quality.
Source: EPA Water Quality Portal sampling records, Ontario MECP, last sampled 2025-08-20. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Good clarity, visible to about 13.1 ft. Phosphorus level: 17.6 µg/L. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4 m | B |
| Phosphorus | 17.6 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
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Fishing Red Horse Lake
Location
County Ranking
Ranked #19 of 34 lakes in Leeds and Grenville Counties
Nearby Lakes in Leeds and Grenville Counties
Explore Red Horse Lake across LakeGrade
More Ontario Lake Rankings
Other Grade A Lakes in Ontario
Mesotrophic Lakes in Ontario
More records, surveys & data sources
Where this data comes from
Measurements for Red Horse Lake 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: 2025-08-20
Monitoring stations: