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LakeQuality

Data Report · Updated July 2026

The State of Nevada’s Lakes 2026

Of 78 monitored lakes in Nevada, 20.5% earn a water-quality grade of A or B and 38.5% score D or F (average grade C). Nla Lake is the cleanest;

78
Monitored lakes graded
C
Average grade
20.5%
Grade A or B
0%
On impaired list

Nevada grade distribution

A
B
C
D
F
A: 6 (7.7%)B: 10 (12.8%)C: 32 (41.0%)D: 19 (24.4%)F: 11 (14.1%)

Cleanest lakes in Nevada

Highest combined water-quality score, 2026.

  1. 1.ANla Lake — Elko County16.1 ft clarity · 3 µg/L P · 1 µg/L chl-a
  2. 2.ANla Lake — White Pine County14 µg/L P · 1 µg/L chl-a
  3. 3.ANla Lake — Nye County6.6 ft clarity · 23 µg/L P · 1 µg/L chl-a
  4. 4.BNla Lake — Clark County0.9 ft clarity · 44 µg/L P · 2 µg/L chl-a
  5. 5.BNla Lake — Clark County4.8 ft clarity · 20 µg/L P · 3 µg/L chl-a
  6. 6.BBoulder Reservoir — Washoe County50 µg/L P
  7. 7.BOnion Valley Reservoir @ Dam — Humboldt County50 µg/L P · 1 µg/L chl-a
  8. 8.BIllipah Reservoir — White Pine County30 µg/L P · 1 µg/L chl-a
  9. 9.BComins Reservoir — White Pine County30 µg/L P · 1 µg/L chl-a
  10. 10.BNla Lake — Washoe County70 µg/L P · 2 µg/L chl-a

Most-polluted lakes

Lowest combined water-quality score among monitored lakes.

  1. 1.FSheep Creek Middle Reservoir — Elko County3.0 ft clarity · 165 µg/L P · 64 µg/L chl-a
  2. 2.FWildhorse Reservoir — Elko County5.9 ft clarity · 107 µg/L P · 76 µg/L chl-a
  3. 3.FWillow Creek Reservoir East — Elko County480 µg/L P · 4014 µg/L chl-a
  4. 4.DWildhorse Res South Basin Lake — Elko County3.3 ft clarity · 71 µg/L P · 158 µg/L chl-a
  5. 5.DKnott Creek Reservoir — Humboldt County145 µg/L P · 33 µg/L chl-a
  6. 6.DWalker Lake — Mineral County4.7 ft clarity · 660 µg/L P · 13 µg/L chl-a
  7. 7.DNla Lake — Humboldt County4.6 ft clarity · 137000 µg/L P · 8 µg/L chl-a
  8. 8.DNla Lake — Washoe County1.0 ft clarity · 230000 µg/L P · 10 µg/L chl-a
  9. 9.DNla Lake — Elko County7.2 ft clarity · 43000 µg/L P · 13 µg/L chl-a
  10. 10.DWildhorse Res North Basin Lake — Elko County9.8 ft clarity · 88 µg/L P · 20 µg/L chl-a

Worst algae hotspots

Highest measured chlorophyll-a (algae) concentration.

  1. 1.FWillow Creek Reservoir East — Elko County4014 µg/L chlorophyll-a
  2. 2.DWildhorse Res South Basin Lake — Elko County158 µg/L chlorophyll-a
  3. 3.FWildhorse Reservoir — Elko County76 µg/L chlorophyll-a
  4. 4.FSheep Creek Middle Reservoir — Elko County64 µg/L chlorophyll-a
  5. 5.DMountain View Lake — Elko County50 µg/L chlorophyll-a
  6. 6.DSpooner Lake — Douglas County41 µg/L chlorophyll-a
  7. 7.DKnott Creek Reservoir — Humboldt County33 µg/L chlorophyll-a
  8. 8.DWildhorse Res North Basin Lake — Elko County20 µg/L chlorophyll-a

Explore Nevada lakes

Lake Fishing Forecast

Species activity outlook by water temperature and season

Grades combine Secchi clarity, total phosphorus, and chlorophyll-a from the EPA Water Quality Portal and state agencies. See the full methodology, the national State of America’s Lakes report, or all Nevada lakes.

Cite this report: LakeQuality, “The State of Nevada’s Lakes 2026,” lakequality.org/report/nv.