Updated Aug 2026
Nevada Lake Water Quality
Water quality grades for 56 monitored lakes across 12 counties.
Nevada has 56 graded lakes in our dataset, sampled across 12 counties, drawing on monitoring by the Nevada Division of Environmental Protection plus federal and volunteer measurements. Only about 7% of Nevada's lakes pull an A grade — the smaller, agricultural-watershed lakes that dominate the dataset tend to carry persistent nutrient loads. 20% of lakes fall in the D or F brackets.
The state's lakes lean eutrophic: enough nutrient input to support an active algal community, with the trade-offs in clarity and dissolved oxygen that come with it. White Pine ranks highest on average county grade (A). Elko sits lowest. With only 12 counties in the state, the cross-county spread is narrower than the within-county spread for most lakes.
Grade Distribution
All 56 Nevada lakes in the index: 23 (41.1%) carry an A–F grade and 33 (58.9%) are not rated, because they lack enough recent nutrient or algae sampling to support a letter.
Where to stay near Nevada
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Top-Graded Nevada Lakes
The highest water-quality grades in Nevada — clarity, depth, and A-F grade at a glance.
Lake Map
Explore Nevada Lakes
Nevada reports, fishing & travel
Reservoirs in Nevada
View all 23 reservoirs →23 of 56 Nevada lakes (41%) are man-made reservoirs in the USACE National Inventory of Dams. 14 carry a High or Significant hazard rating. The oldest matched dam dates to 1910.
EPA-Impaired Lakes in Nevada
View all 31 impaired lakes →31 of 56 Nevada lakes (55%) are officially listed as impaired under Clean Water Act §303(d) in the most recent EPA ATTAINS reporting cycle. 1 have an approved Total Maximum Daily Load (TMDL) restoration plan.
Nevada Fishing & Recreation
Licenses, regulations, records, and where to fish across Nevada.
Counties
All 12 Nevada counties, ranked by average lake water quality. Compare them against every county nationwide in the county rankings, browse the full directory of graded lakes, or pick a different state.
Cleanest Nevada Lakes
23 lakes23 graded lakes
| # | Lake | County | Grade | Clarity | Trophic | Access |
|---|---|---|---|---|---|---|
| 1 | AComins Reservoir | White Pine | A | No recent samples | Oligotrophic | Not recorded |
| 2 | ALake Tahoe | Douglas | A | No recent samples | Oligotrophic | ✓ Public |
| 3 | ALake Tahoe | Washoe | A | No recent samples | Oligotrophic | ✓ Public |
| 4 | ALake Tahoe | Douglas | A | No recent samples | Oligotrophic | Not recorded |
| 5 | BIllipah Reservoir | White Pine | B | No recent samples | Mesotrophic | ✓ Public |
| 6 | CWildhorse Res South Basin Lake | Elko | C | 3.3 ft | Eutrophic | ✓ Public |
| 7 | CRye Patch Reservoir | Pershing | C | No recent samples | Mesotrophic | ✓ Public |
| 8 | CChimney Reservoir West Lobe | Humboldt | C | No recent samples | Mesotrophic | ✓ Public |
| 9 | CBoulder Reservoir | Washoe | C | No recent samples | Eutrophic | Not recorded |
| 10 | COnion Valley Reservoir @ Dam | Humboldt | C | No recent samples | Eutrophic | Not recorded |
| 11 | CSquaw Creek Reservoir | Washoe | C | No recent samples | Eutrophic | Not recorded |
| 12 | CSpooner Lake | Douglas | C | No recent samples | Eutrophic | Not recorded |
| 13 | DWalker Lake | Mineral | D | 4.7 ft | Eutrophic | Not recorded |
| 14 | DSheep Creek Lake | Elko | D | 6.2 ft | Eutrophic | Not recorded |
| 15 | DWildhorse Res North Basin Lake | Elko | D | 9.8 ft | Eutrophic | Not recorded |
| 16 | DRye Patch Reservoir North | Pershing | D | No recent samples | Eutrophic | Not recorded |
| 17 | DBilly Shaw Lake | Elko | D | No recent samples | Eutrophic | Not recorded |
| 18 | DLahontan Reservoir | Lyon | D | No recent samples | Eutrophic | Not recorded |
| 19 | DMountain View Lake | Elko | D | No recent samples | Eutrophic | Not recorded |
| 20 | DBilk Creek Reservoir | Humboldt | D | No recent samples | Eutrophic | Not recorded |
| 21 | DWall Canyon Reservoir | Washoe | D | No recent samples | Hypereutrophic | Not recorded |
| 22 | FWildhorse Reservoir | Elko | F | 5.9 ft | Hypereutrophic | Not recorded |
| 23 | FKnott Creek Reservoir | Humboldt | F | No recent samples | Hypereutrophic | Not recorded |
Nevada Lakes Needing Attention
23 lakes23 graded lakes
| # | Lake | County | Grade | Clarity |
|---|---|---|---|---|
| 1 | FKnott Creek Reservoir | Humboldt | F | No recent samples |
| 2 | FWildhorse Reservoir | Elko | F | 5.9 ft |
| 3 | DWall Canyon Reservoir | Washoe | D | No recent samples |
| 4 | DBilk Creek Reservoir | Humboldt | D | No recent samples |
| 5 | DMountain View Lake | Elko | D | No recent samples |
| 6 | DLahontan Reservoir | Lyon | D | No recent samples |
| 7 | DBilly Shaw Lake | Elko | D | No recent samples |
| 8 | DRye Patch Reservoir North | Pershing | D | No recent samples |
| 9 | DWildhorse Res North Basin Lake | Elko | D | 9.8 ft |
| 10 | DSheep Creek Lake | Elko | D | 6.2 ft |
| 11 | DWalker Lake | Mineral | D | 4.7 ft |
| 12 | CSpooner Lake | Douglas | C | No recent samples |
| 13 | CSquaw Creek Reservoir | Washoe | C | No recent samples |
| 14 | COnion Valley Reservoir @ Dam | Humboldt | C | No recent samples |
| 15 | CBoulder Reservoir | Washoe | C | No recent samples |
| 16 | CChimney Reservoir West Lobe | Humboldt | C | No recent samples |
| 17 | CRye Patch Reservoir | Pershing | C | No recent samples |
| 18 | CWildhorse Res South Basin Lake | Elko | C | 3.3 ft |
| 19 | BIllipah Reservoir | White Pine | B | No recent samples |
| 20 | ALake Tahoe | Douglas | A | No recent samples |
| 21 | ALake Tahoe | Washoe | A | No recent samples |
| 22 | ALake Tahoe | Douglas | A | No recent samples |
| 23 | AComins Reservoir | White Pine | A | No recent samples |
Lake Match
Which lake suits how you actually use one?
Six questions — swimming, fishing, quiet, cabins, drive time — and a shortlist of graded lakes that fit, with the water quality behind each one.
Source: EPA National Aquatic Resource Surveys and the EPA Water Quality Portal.
More on lake water quality
The top-graded lake in every state we cover, picked grade-first with water clarity as the tie-breaker — plus the states whose winner is still not clean.
State-by-state Secchi champions: the clearest measured lake in each U.S. state we grade, which is not the same as the cleanest nutrient grade.
A data snapshot of the lakes we grade: how the A–F distribution breaks down, the clearest and the greenest states, and where the water is improving.
How lakes are graded A–F on nutrients and algae using EPA ecoregion condition classes, what each letter means in the water, and why an A is not a clearance.