What is the water quality grade for Upper Klamath Lake?

Upper Klamath Lake in Klamath County, Oregon received a water quality grade of F (Very Poor). Chlorophyll-a (algae): 71.6 µg/L.

Is Upper Klamath Lake safe to swim in?

Avoid swimming, very poor water quality, potential algae toxins. Upper Klamath Lake has an overall water quality grade of F. Algae concentration (chlorophyll-a) is 71.6 µg/L. Always check local health department advisories before swimming.

Klamath County, Oregon · 42.41°N

Upper Klamath Lake

Grade FVery Poor water quality

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Limited DataHypereutrophic

Upper Klamath Lake is a highly nutrient-loaded hypereutrophic lake in Klamath County, Oregon. Water quality is graded F based on 1 sampling years through 2025. Compared to the 19 other monitored lakes in Klamath County, Upper Klamath Lake ranks #20 for water quality.

Source: EPA Water Quality Portal sampling records, Oregon DNR, last sampled 2025-10-01. Grade methodology: LakeGrade methodology.

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Swimming Safety

Avoid swimming, very poor water quality, potential algae toxins

Water Quality Grade: F, Very Poor

No clarity data. Chlorophyll-a: 71.6 µg/L. Trophic State Index: 72.

Metric	Value	Grade
Water Clarity (Secchi Depth)	No data
Phosphorus	No data
Chlorophyll-a (Algae)	71.6 µg/L	F
Trophic State Index (TSI)	72	Hypereutrophic

Very high nutrients, dense algae, poor clarity

Where to stay near Upper Klamath Lake

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