What is the water quality grade for Isle la Motte Lake?

Isle la Motte Lake in Grand Isle County, Vermont received a water quality grade of A (Excellent). Water clarity: 15.1 ft visibility. Phosphorus: 19.9 µg/L. Chlorophyll-a (algae): 3.2 µg/L.

Is Isle la Motte Lake safe to swim in?

Excellent for swimming, crystal clear water with minimal algae. Isle la Motte Lake has an overall water quality grade of A. Algae concentration (chlorophyll-a) is 3.2 µg/L. Always check local health department advisories before swimming.

Grand Isle County, Vermont

Isle la Motte Lake

Grade AExcellent · 15.1 ft clarity

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Mesotrophic

Isle la Motte Lake is a mesotrophic lake in Grand Isle County, Vermont. Water quality is graded A based on 3 sampling years through 2025. Compared to the 2 other monitored lakes in Grand Isle County, Isle la Motte Lake ranks #1 for water quality.

Source: EPA Water Quality Portal sampling records, Vermont DNR, last sampled 2025-08-21. Grade methodology: LakeGrade methodology.

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Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

Water Quality Grade: A, Excellent

Crystal clear, you can see 15.1 ft down. Phosphorus level: 19.9 µg/L. Chlorophyll-a: 3.2 µg/L. Trophic State Index: 42.

Metric	Value	Grade
Water Clarity (Secchi Depth)	15.1 ft	A
Phosphorus	19.9 µg/L	A
Chlorophyll-a (Algae)	3.2 µg/L	A
Trophic State Index (TSI)	42	Mesotrophic

Moderate nutrients, good water quality

Where to stay near Isle la Motte Lake

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