Lake Mcdonald is a mesotrophic lake in Flathead County, Montana. Water quality is graded B based on 2 sampling years through 2018. Compared to the 79 other monitored lakes in Flathead County, Lake Mcdonald ranks #77 for water quality.
Source: EPA Water Quality Portal sampling records, Montana DNR, last sampled 2018-09-19. Grade methodology: LakeGrade methodology.
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Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
No clarity data. Phosphorus level: 39.5 µg/L. Chlorophyll-a: 0.7 µg/L. Trophic State Index: 42.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 39.5 µg/L | C |
| Chlorophyll-a (Algae) | 0.7 µg/L | A |
| Trophic State Index (TSI) | 42 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Lake Mcdonald
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Fishing Lake Mcdonald
Location
County Ranking
Ranked #77 of 80 lakes in Flathead County
Cleaner Lakes Within 30 Miles
Lake Mcdonald holds Grade B. 4 nearby lakes hold higher grades.
- AHalfmoon LakeFlathead County · 4.3 mi · Higher grade (B → A)
- ALake FiveFlathead County · 4.7 mi · Higher grade (B → A)
- ABailey LakeFlathead County · 7.6 mi · Higher grade (B → A)
- ALake McdonaldFlathead County · 3.3 mi · Higher grade (B → A)
Nearby Lakes in Flathead County
Explore Lake Mcdonald across LakeGrade
More Montana Lake Rankings
Other Grade B Lakes in Montana
Mesotrophic Lakes in Montana
More records, surveys & data sources
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2018-09-19
Monitoring stations: 3