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LakeQuality
Late afternoon sun over Slim Lake, scattering a bright path across wind-textured water
NR

Kootenai County Lake Quality

Idaho, 22 lakes — no lake here has enough monitoring data for a grade

There are 22 monitored lakes in Kootenai County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. No lake in Kootenai County has enough sampling behind it for an A–F grade yet. The 22 monitored lakes below carry whatever clarity, phosphorus, and chlorophyll-a measurements exist.

Most of the county's monitored lakes are shallow, under 50 feet, which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed.

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Where to stay near Kootenai County

Top-rated places to stay near Kootenai County

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Quick Answers for Kootenai County

Cleanest lakes in Kootenai County →Cleanest lakes in Idaho →Safest swimming lakes in Idaho →

Planning a trip? Check special fishing regulations for Usgs Lake — or check the official Idaho fishing regulations.

All Lakes in Kootenai County

22 lakes · 0 graded, 22 not rated0 graded lakes · 22 not rated, hidden

#LakeGradeClarityPhosphorusAlgaeTrophicAccess
NRUsgs LakeKootenaiNRNo recent samples6.5 µg/L1.7 µg/LNo recent samples✓ Public
NRIdeq LakeKootenaiNRNo recent samples5.5 µg/L1.1 µg/LNo recent samples✓ Public
NRCoeur D' Alene LakeKootenaiNRNo recent samples12 µg/LNo recent samplesNo recent samples✓ Public
NRThompson LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samples✓ Public
NRAnderson LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samples✓ Public
NRThompson LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRHarrison SloughKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRChatcolet LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRBlue LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRSwan LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRBlack LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRMedicine LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRCave LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRKillarney LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRRose LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samples✓ Public
NRLake HaydenKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRAlpine LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRChilco LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRAvondale LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRFernan LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRHauser LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samples✓ Public
NRSpirit LakeKootenaiNRNo recent samplesNo recent samplesNo recent samplesNo recent samples✓ Public

NR = not rated: there is not enough recent sampling to support a letter. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.

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Other Counties in Idaho

Gem County

2 lakes · Avg grade A

Canyon County

2 lakes · Avg grade A

Bear Lake County

3 lakes · Avg grade C

Valley County

26 lakes · Avg grade C

Bonneville County

9 lakes · Avg grade C

Blaine County

12 lakes · Avg grade D

See how Kootenai County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all United States (49 states), Canada (Ontario, Québec, Nova Scotia, British Columbia and Newfoundland and Labrador), and 38 other country hubs..

Source: EPA National Aquatic Resource Surveys, 2026.