Is Ril Lake safe to swim in?

Good for swimming, clear water with low algae levels. Ril Lake has an overall water quality grade of B. Always check local health department advisories before swimming.

Muskoka District County, Ontario · Water Quality Report Card

Ril Lake

Grade B — Good

Oligotrophic

Ril Lake in Muskoka District, Ontario received a water quality grade of B (Good). Water clarity: 2.9 m visibility. Phosphorus: 7.5 µg/L.

Clarity: 2.9 m
Type: Oligotrophic

Where to stay →Safe to swim?

Ril Lake is a cold, clear oligotrophic lake in Muskoka District County, Ontario. Water quality is graded B based on 2 sampling years through 2025. Compared to the 169 other monitored lakes in Muskoka District County, Ril Lake ranks #123 for water quality.

Source: EPA Water Quality Portal sampling records, Ontario MECP, last sampled 2025-10-14. 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 9.5 ft. Phosphorus level: 7.5 µg/L. Trophic State Index: 39.

Metric	Value	Grade
Water Clarity (Secchi Depth)	2.9 m	C
Phosphorus	7.5 µg/L	A
Chlorophyll-a (Algae)	No data
Trophic State Index (TSI)	39	Oligotrophic

Low nutrients, clear water, excellent for swimming

Where to stay near Ril Lake

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Fishing Ril Lake

→ Ril Lake fishing regulations (limits, seasons, special rules)

Location

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County Ranking

Ranked #123 of 170 lakes in Muskoka District

Cleaner Lakes Within 30 Miles

Ril Lake holds Grade B. 3 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Muskoka District

Explore Ril Lake across LakeGrade

Lake Fishing Forecast

Species activity outlook by water temperature and season

Oligotrophic Lakes

Low nutrients, clear water, excellent for swimming

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All Ontario lakes

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Other Grade B Lakes in Ontario

Haliburton · 3 m

Haliburton · 3 m

Haliburton · 2.9 m

Haliburton · 3.2 m

Haliburton · 2.1 m

Haliburton · 1.8 m

Oligotrophic Lakes in Ontario

Raven Lake Otter Lake St Nora Lake Clinto Lake

More records, surveys & data sources

Where this data comes from

Measurements for Ril 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: 2025-10-14

Monitoring stations:

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